Grottle - Grottle will probably stay Grottle since Ash onlyseems to evolve one starter to it's final stage in some of the series (Charizard & Sceptile) Alternate series. He had no Typhlosion, Feraligatr or Meganium in his stint in Johto. Then again... Ah well. Could go either way.
Gliscor - I doubt Ash will be dropping Gliscor anytime soon Me neither.
Staraptor - Ash will always keep one bird in his line-up. How else are they going to look for TR's balloon? With another bird? :X Then again, that's assuming Staraptor will no longer be on Ash's team, which I doubt.
Infernape - This will probably be the last pokemon standing in the Sinnoh League battle and be used to beat Paul. Either this, or Pikachu. That it'd evolve into Monferno is a given, but Infernape? Could go either way.
Buizel - Buizel is awesome as it is. *Looks at Kingler* Could be... or... *looks at Corphish* ... not.
Pikachu - No-brainer Obviously. XP
Mamoswine Quite obvious. Though chances are it could be released or something in Johto... *remembers the time when Ash left his Charizard for training*
Prinplup - I think it'll evolve, but only once. Hard to do so with an Everstone. :P
Pachirisu Most likely.
Lopunny - It'll evolves and still keep her crush on pikachu .See above
Leafeon - Well since May has her Glaceon it would only make sense that Dawn would get a Leafeon Again, see above.
Misdreavous - Just a hope here, because none of the characters have ever had (and kept) a ghost type And you forgot to consider a Johto starter, which'd have been more likely? O_o
Croagunk - Someone's got to babysit Brock Well said.
Blissey - With the way Brock treats his pokemon and his skill as a Breeder, there's no doubt it'll evolve into a Blissey We'll definitely see his Chansey somewhere in Johto, and also a Blissey in the anime, but whether he'll get the final stage before the end of Johto... well, again, either way.
Sudowoodo Quite likely.
Rhypherior - Because we've yet to see one, and it would keep his rock theme going Keep it going? Sudowoodo isn't enough? :X
Altaria - Because isn't it about time SOMEONE got a dragon type? I can only hope on this one. Unlikely, but... no comment.