I think we will see Taliesin will play something new and experimental, unless Matt is tapped out of ideas. My guess is a Rune Child or whatever Gilmore is, or maybe Aeormaton.
Liam I think may play a Paladin or a Monk. Someone devoted to something greater than themselves, who can be lethal as hell. He loves call backs enough i wouldn't be surprised by a Shadar-kai devoted to the Raven Queen, or an Ashari, though he just played one in EU.
Sam will play something silly. Possibly something small again, maybe an animal person? A grung fey ranger would be pretty great. What races are common in Marquet?
Laura I think might play one of the things she hasn't played due to someone else having a character concept for that class already, so a rogue or warlock.
Travis is a tough one, because he seemed to miss playing a simple beat stick, but also enjoyed being smart and tactical. Maybe a Battlemaster Fighter or something like that, that kinda lets him do both?
Marisha and Ashley I don't even have any guesses. Marisha will probably play something challenging and versatile, but Ashley gets to be fully dialed in to the game for the first time, so who knows.
I hope someone plays an artificer!