Just a speculation. Obviously it seems "SM is the new DP" is not going to be happening this series (unless the school is some distant connection to the camp arc), but I like to think there might be a team similarity like in BW and XY.
Besides, all those mons 'fit' Ash, and two lines are already confirmed.
Since you have been asking several times now. This is my opinion, most people tend to agree on most of these however.
T-1: GPICSS
T-2: Swellow, Glalie, Gliscor, Bulbasaur, Krookodile, Heracross, Kingler, maybe Hawlucha
T-3: Hawlucha, Gible, Talonflame, Torterra, Squirtle, Pignite, Corphish, Quilava, Buizel, Staraptor
T-4: Goodra, Noctowl, Tauros, Donphan, Noivern, Leavanny, Bayleef, Torkoal, Palpitoad
T-5: Muk, Boldore, Unfezant, Snivy, Oshawott, Scraggy, Totodile
Excluding: Butterfree, Primeape, Pidgeot, Lapras [all released] & Rowlett