Well, she wouldn't be the first Maquis to have survived the Jem'Hadar. I mean, Eddington and Sisko also rescue a bunch of them, too. Wouldn't be that surprising if there were more.
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I think the biggest difficulties with canon is really the whole Changling ability set isn't always consistent or at least clear. Sometimes Changlings in DS9 (or at least Odo, when he's accused of murdering someone he has investigated, and when he unwittingly turns into a monster) have DNA, sometimes they seemingly don't.
Ultimately, it seems weird that it's hard to detect a changling masquering as a glass if they have DNA, because glass doesn't have DNA (usually), so if you can detect DNA in your glass, it must be a changling. On the other hand, it might make sense if Changlings used DNA when replicating cells because that's kinda a proven way to "replicate" and "operate" organic bodies. But well, they don't in Picard.