Speculation on Pokemon Ash would catch if there is a filler series in the anime?

If the anime has a short filler series, such as the Battle Frontier, before generation 6's season starts, what additional pokemon could you envision ash catching and/or which of the pokemon he already owns will evolve?

If they have a filler season I could see one of the main characters at least getting one of the gen VI Pokemon just like Misty got Togepi in Kanto, May got Munchlax in Hoenn and James got Mime Jr. in Kanto (Battle Frontier).
I would like Ash to get his Primeape back as we never got to see much of it and would be nice to see Butterfree again even if he doesn't rejoin Ash. Also Pidgeot would be cool to see again and maybe even Lapras and Gliscor and Haunter and Larvitar or how about just all of his old Pokemon that he doesn't have anymore.

Since Ash's Charizard has formally rejoined his team, and it has been announced that the bridge series will take place on an island chain much like the Orange Islands, I can see a return of Lapras as very likely. Also, with speculation that Ash may release fan-favorite Oshawott, it's exceedingly likely that former Kanto members of Ash's team make reappearances, as oppose to him catching new pokemon.

Bring back gible and evolve it to atleast a gabite evolve since Charizard is back pig note won't become emboar so atleast have snivy become servine than serperior right before the last BW episode I don't feel ash should catch any 1 else but it does present a opportunity to evolve older pokes p.s Give us another raichu episode thanks