Personally, I thought it was a missed opportunity to not include either or both of the girls' parents when we see the flashback showing the attack on Mars in the series. I know why it couldn't be done, Children of Mars was written and filmed after Picard was finished and filmed in Toronto using Canadian actors, vs Picard being filmed in California with American actors. Still think it would have been a cool nod all the same though.
Pretty sure the ships that attacked the surface were the ships that would have been defending Utopia Planitia Shipyards. That would be a shame. Those kids were supposed to be about 12 years old in 2385; that means they'd be around 26 in PIC's 2399 setting. I think there's some dramatic potential there.
Oh, I'm not doubting the potential. I just think that, for the producers, that Short Trek was one and done.