Lalah's Past
In Lalah’s first appearance, she is an orphan with a mysterious past and no apparent living relatives. But many spin-offs tell a different story. She now has all kinds of tragic backstories and many relatives. Personally, I like how First leaves her background up to the imagination, but I decided to compile all her official origin stories here, plus information about her family members.
Note: Lalah's comrade has many names but she calls him "Taisa" ("Captain" in English) so that's what I'll be referring to him as here.
⚠️ CW: Some of these stories include child abuse and other disturbing themes. ⚠️
First Gundam
In Encounters in Space, Lalah pledges loyalty to the Zeon war effort. She tells Kycilia that the military saved her- but saved her from what exactly? The original anime does not tell us, though we can assume it must have been extremely awful if Lalah considers being an experimental fighter pilot in outer space to be a step-up that deserves gratitude.
Mobile Suit Gundam: Awakening
"You were absolutely on target in recommending Lala Sun. She's a second-generation space colonist, from the Ruum colony on Side 5, and although her family was killed later in flight, the very fact that they were spared during the Battle of Ruum may in large measure be due to Lala's own considerable abilities."
This novel written by Tomino contains Lalah’s earliest backstory. She is a Spacenoid from Loum. Her parents were killed in the One Year War. After her parents are killed, she boards a Zeon warship. After that, the text is vague on the details, but she is apparently treated terribly by everyone until she runs into her "Taisa." He suspects she may be a newtype and so she is recommended to the Flanagan Institute. Doctor Flanagan is impressed by her abilities. Six months later, Taisa delivers the Elmeth to Side 6 and is surprised to hear that Lalah will be piloting it.
Turning to Doctor Flanagan, a shocked Sha exclaimed in spite of himself, "This potential pilot you've been talking about for the Elmeth-Bit system . . . You meant Lala, didn't you?"
"Correct."
And so, Lalah becomes an ensign.
"Lala?"
"Yes?"
"I know the researchers at the agency must have inspected every pore in your body and analyzed every memory you have. I want to apologize."
"You don't need to, Commander," she said, placing her hand on top of his and shaking her head. "When my parents died, I was devastated. You gave me a reason to go on living. And I'm grateful for it. And besides, this assignment means I'll be with you. I'm happy."
"That makes me feel better, Lala."
"I was picked up by a Zeon warship after I lost my mother and father, and I did whatever I had to to survive until I arrived here at Side 6. I had no choice. And it was the same after I got here. I'm just grateful that I met you as soon as I did, before I became a physical and mental wreck. Now I'm going to be working with you. Just think of it. Suddenly, I've even been made an ensign!" Somehow Lala managed to laugh.
Secret Rendezvous: Amuro and Lalah

Lalah illustration from the novel Secret Rendezvous.
"Lalah Sune’s earliest memories were of the orphanage in the crowded streets of
Delhi, and she grew up living a life that was almost entirely self-sufficient. Some of the
children from that facility were taken by families emigrating to space, but in Lalah’s case
she left at age nine, when the owner of Cabas asked to adopt her. None of the staff
members at the orphanage seemed to care about the identity of the adults who took the
children. Even though they knew they couldn’t survive on their own, the orphanage
would throw them out as soon as they turned fifteen."
This novel is also by Tomino, but it was written years later and has a different backstory. This time she is an Earthnoid from Delhi, India. She was orphaned at a young age and can’t remember her original parents. She is adopted by an un-named man when she is nine years old. Then when she is seventeen, she becomes a prostitute at the brothel he owns.
At some point after that, Taisa feels Lalah "calling out" to him mentally and he pays to see her, but they don't have sex. He asks her if she wants to come with him to space, but she is undecided. Later she decides to leave the brothel and she happens to run into him again, which is lucky because some people were trying to force her to go back. After boarding the Zanzibar ship, Taisa asks Lalah what she wants to do.
“Even if you were only picking up on the atmosphere, your intuition is good. Would you allow me to make use of it?”
“It’s almost as if you mean to make me into a soldier.”
“That’s correct.”
“...”
“I won’t force you. If your answer is no, I’ll land the ship right now.”
“You’re joking…” Lalah started to laugh, but when she realized the young man was serious she closed her mouth.
The other young officer standing at the door chuckled at their friendly conversation, while also making it clear that Char wasn’t lying. It seemed like he felt even more embarrassed about this than she did…
The ship was gaining altitude as it orbited the Earth, but even as they spoke it wouldn’t have been out of the question to go back. Besides, Char was also thinking that it would be a good idea to land at least once for practice, as part of breaking in the new ship, but he didn’t mention that part. However, Lalah could tell that too, and she took her time deliberating.
“If you want to return to Cabas, that’s fine. Or if you’d like to live on your own, I can at least provide you with a small bit of support.”
“We’ve only met once before. Why would you go that far?”
“I believe I’ve made my intentions known.”
“I can’t imagine what I’ll be asked to do, but if my abilities can be of use to the Lieutenant Commander then I don’t want to disregard them…this isn’t me being conceited, okay?”
Contrary to common fandom belief, this was not Lalah's original intended backstory. Tomino himself predicted people would spread this rumor but it isn't true. He said so in the novel's afterword:
"In the future, this novel will likely come to be critiqued as the original story of the
television and movie versions of Mobile Suit Gundam, but that will be incorrect. This
story was originally published in 1997 for Kadokawa’s Mini Bunko label, twenty years
after the television series, and it was corrected and reorganized to be more novel-like for
the Sneaker Bunko reprint."
Gundam the Origin
In Gundam the Origin, Lalah is living in Brazil, but her family is back in Mumbai, India. She has only a single photograph of them, but it is water-damaged. She warms up to Taisa after he offers to touch it up with a computer for her.
Lalah’s newtype abilities are being exploited by an abusive gambler. Lalah says she is sending money home to her family, but it’s clear that any money she receives is just a tiny fraction of what she earns for the gambler. The gambler hits Lalah when she doesn’t cooperate with his cheating and he has also forbidden her from talking to other people.
Word of Lalah’s powers spread, and the gambler is killed by Agha, who works for a rival who also wants to exploit her in a casino. But when Agha attempts to take Lalah, Taisa kills him with a shovel. After that, Taisa asks Lalah if she wants to go to space. As for her family members, they are not mentioned again in this story.
For the Barrel
Lalah has a son named Caspar Bailey (or Casval Bailey, if we were to go by modern transliterations) in For the Barrel, an extremely cursed and cringe Gundam project from the early 2000s. Unfortunately... he is the result of half-sibling incest, although I'm not sure if his parents were aware of this when they got together. The writing is very vague. In this story, "Lalah Sung" is raised by the Flanagan Institute since infancy, but she's actually the daughter of Zeon Deikun and a woman from Nepal. (Miss Sung I suppose - no first name is given.) This also makes her and Sayla half-sisters. Normally these characters aren’t related at all.

Lalah's "For the Barrel" redesign. For the Barrel's art is good, but the writing is terrible.
As for Lalah herself, she gets to live in this story because Amuro (renamed Abao) is too scared to fight her. But for some reason she never contacts her son, who was abandoned and believes he's an orphan. Half true since the original Casval died young for some unexplained reason... There is no Red Comet in this, and no Zabis either. For the Barrel is awful and makes no sense. Some of it is way too gross for me to want to describe, but thankfully, someone else made a post with a list of its many issues and a link to a fan translation.
Char’s Daily Life
This manga takes place in modern-day Japan; however, it also is implied to be the next life for Gundam characters who have been reborn, so it takes place both before and after the Universal Century! Lalah's surname is "蘭" (click here for pronounciation) which means "yew." She is a high school student who also works part-time at a kindergarten, alongside her coworker and friend "Nishi" (Taisa.)
Lalah initially struggles at her job and admits she doesn't understand how to take care of children well because her own childhood was rough. Her father used to beat her and her parents are divorced. Her father later appears and looks for her because he wants to borrow money, but Nishi scares him off. Her mother is never shown.

Lalah's father.
Others
Lalah and Taisa in SD Gundam Gaiden, a fantasy spin-off series.
There are many mangas I have not read yet, plus many video games I haven't played, so there may be other backstories for Lalah I don't know about yet. This page may be updated in the future.
Conclusion
There is an official magazine called Gundam Fact File which contains fact sheets for different Gundam characters. On Lalah's page, Lalah's two Tomino novel backstories are both acknowledged as "theories." It then goes on to say that, regardless of the details, Lalah wasn't in a good environment and she feels gratitude towards Taisa for helping her out.
I agree with this take. Her three UC backstories (Awakening, Secret Rendezvous, Origin) all have similar themes. Lalah is suffering in a bad environment until being helped by Taisa. After this she becomes very protective of him in return. As for how this happened specifically, that's up to your imagination. They're all just "theories."
Gundam.info, the official Gundam website, says that Lalah was "plucked from poverty" and doesn't elaborate beyond that.