With the fact of the process of Cold Lights in mind, these are the speculations what the protagonists of Chiasmata did before they got Coldlit and ended up without memory in the Location. Expect a lot of links here - just to make sure all of the facts are facts.
Essentially, this is the Chiasmata version of this (spoileriffic) post.
Eukaryota
Prokaryota
Her flavour quote at her civilian reference is an interesting one - 'I brought the peace' (tying in to her dearest memory, making a difference) and now it's been revealed she's actually Isochrone who used to be a policewoman, we finally know where this quote pertains to: the police brings peace by incarcerating criminals. She might've also been an athlete - it is stated she likes hiking, is a keen swimmer and she was taking skating as a hobby.
Clara was a phd student, and apparently very enthusiastic about it. May have been about radioactivity, based on her knowledge about half-lives. However, she disliked living alone, which may say she didn't got a significant other. There is also the implication she was a writer, at least, in her free time. Her dearest memory is finding something new. This might be literally, discovering a new specie of plant/animal or something else, but it is kind of likely several of these are not meant to be like that. Her flavour quote at her civilian reference is 'I heard the dead' - certainly ominous.
Leonardo was a painter, and, aside from it being a hobby, some of it was even non-amateur. His memory was impressing someone - one might guess by a painting. His flavour quote at his civilian reference is 'I worked my arts', confirming it.
Omar is said to not like his occupation and has not seen a family member for over a year. The more optimistic guess is that he was a soldier, seeing his origin (the Middle-East). His flavour quote at his civilian reference is 'I cut a deal'. In the military, deals are cut with some regularity. He is ironically enough terrified of fire, at least, used to be, which may root deep and can tie into this. However, the evidence behind this theory is fairly shaky as his hobby is graffiti. The more pessimistic guess is that he was a drug dealer, as it is said that the graffiti wasn't the only illegal thing he did, which may explain why he didn't like his job much. He might've been forced, as the previous link says: 'Not like he did many illegal things because there were scant other options'. His dearest memory was getting out of something. In the military context, it may be literal, getting out of a war front or a crashing building. In the dealer context, it could be figuratively, like getting out of the grasp of a particularly nasty client, the police or even jail. His distrustful and paranoid personality explains itself in two ways: in the first option, it may be, together with his fear of fire and dislike of loud, sudden noises, the result of being a Shell-Shocked Veteran, and the second option it could be a requirement for the job to be slightly distrustful, as trusting your client is very important to prevent them ratting you out. On another note, he's one of the ones who knew at least one superhuman prior and it's said he does a lot of running around, which may be because he would often have to run away from oppressors or the police if he got caught.
Archaea
David is confirmed to lost his arm when he was fourteen. His flavour quote at his civilian reference was 'I was there before' which might refer to him going through the same trials before as his next generation is. However, his dearest memory was holding a grandchild and he has a son who works in medicine, a daughter who is currently unemployed and three grandchildren. He tries to maintain the contact with them as well. His hobby was knitting, though one may ask themselves how he managed that.
Dawn's dearest memory was kissing a significant other she met on a marine biology course. That person may be one of the superhumans. Her belonging to the set of people who are knowing at least one of them prior can tie into this. Her flavour quote at her civilian reference was 'I watched the sunrise' which is rather fitting seeing her name. Seeing that she is a fan of arctic places, it may have been the aurora borealis/australis as it's confirmed she went there. Dawn may be an arctic biologist too, when you take a look at her clothing and the speculation above. She was also a skiing person and a birdwatcher.
Ash was a part-time English teacher - and a cool one. She liked it as well. Her flavour quote at her civilian reference is 'I trot the globe', so she may have been a traveler, too, as her dearest memory was the first breaths of foreign air. Her description also refers to her as an artist, as her hobby is drawing and reading comics. Strangely enough, Holly (who shares her symbol), is also an artist. Both are named after trees and plants as well.
It's possible Anders was a very lonely guy. He is described as it in the flavour quote at his civilian reference, 'I worked alone'. Furthermore, it is stated that he isn't much of a family man and his hobby was named hiking. His dearest memory was listed as solitude as well. However, his day job is said to be physically rather demanding, whatever it may be.