Dunno if it's the same for everyone but so far:

P.s A 3rd Pokemon only turns up if that person has finished the Elite 4.

Balmut: Ghost; Lampurt, Trevenaunt

"Celia": Ice; Sneasle, Snover, [Blank]

Zul: Rock; Dwebble, Onix, Rhydon

Chrono: Grass; Maractus, Oddish, Sawsbuck

Derf_Vader: Electric; Pachirisu, Stunfisk, [Blank]

S-Meister: Dragon; Noibat, Fraxure, [Blank]

Colbert Jr: Ice; Snover, Beartic, [blank]

"Hanky": Rock; Corsola, Bwebble, [Blank]

"James": Ground; Marowak, Wooper, [Blank]

"Denver K L": Ground; Nincada, Sandshrew, [Blank]

Laith: Normal; Minccino, Dunsparce, [Blank]

TBC

I think there might be a couple none-deckers in this list :/