>>722943267
The only (former) main characters I would ever believe could have a kid is Randy and Mireille.

Kevin and Ries probably took an oath of celibacy or some shit
Lloyd, Rean and Van are all stuck in former-harem hell and by proxy so is every main female character from those games except for Millium and Jusis who won't because Millium is forever stuck being child-coded
Nadia is forever sister-zoned no matter how hard she throws herself at Swin
And I just don't believe Estelle and Joshua have it in them. They're the most likely, though that's not saying much