I think Quin will play around with the lineups to see what combos work best. At 6'5 and 6'6", Mudiay and Exum both can easily be plugged into SG, and there's 20 minutes a game needed there from Korver's departure.
Also depends on how much O'Neale plays and how often Quin goes small with Bojan and Ingles in the lineup together, or big with Davis and Gobert together.
Just assuming minutes and no positions listed, 5*48 = 240
Mitchell (34), Gobert (32), Conley (32), Bojan (32), Ingles (28), O'Neale (25), Davis (20), Green (20) = 223 mins.
That would leave 17 to split between Niang, Exum, Mudiay, Bradley, etc.
Am I forgetting anyone on the current roster? I listed 12 above and think another vet could still be added.
Obviously players miss games, backups get more mins during blowouts (I hope we'll be on the positive side of some of those) and there are always assorted injuries (fingers crossed for no major ones).
So yes, somewhere in the range of 15-25 mins available if everyone's healthy.
My guess is two of Brantley, JWF and Oni get the 2-ways and 1 makes the roster. But all three should play most of the time in the GLeague.