I have some pokes in my mind. Let's try using some future sight shall we?
Meditite: Meditite is a pokemon from the mountains. But since Medicham = Pure Power, i'm expecting an event of some sort.
Bergmite: If that mountain is an ice mountain, then it's time for MOTHERF***ING AVALUGG. I don't even care that it's going to have weakness to gyms in the future, it's AVALUGG. But yeah, ice mountain, so yeah.
Snorunt: Like i said, ice mountain. I hope you guys saved that Dawn Stone for dat Froslass tho.
Gulpin: I don't know why it's not in the game yet. Is it too good, or just not a place for it yet? I don't know.
Cubchoo: Ice baby, ice.
Snover: Maybe as an event. It's the only poke with Snow Warning, after all.
Sneasel: If that's an ice mountain, then i see no better place to put it. Most likely available in the wild since i'm the only person that loves Sneasel like people love Greninja in Gen VI.
That's what i think for the mountain, AND apart from Meditite, all these pokes can only be available if the mountain is an ice mountain. And Gulpin is Gulpin.
And since i have no idea of what Route 2 is, then i don't know what to suggest to that area. But like i said before, i'm expecting fights like the ones in Route 1. We got Tauros vs Bouffalant and Pinsir vs Heracross.
Maybe in Route 2 we're going to have Sableye vs Klefki or something...