1) Just dump any trash pokémon into pokébank, fill it! The more pokémon the more miles you'll get.
2) Wonder Trade like crazy, apparently the real life distance between the trades affects the miles you get, so I usually WT when Japanese people are awake; I guess for you it would be when Americans are trading.
I don't remember where but I read that compatibility for SunMoon won't be at launch, I think it was like a couple months... Sucks but it also goo because then we won't be able to just "swap" living dex and get it fill in a few minutes... We'll have to do it the old way or wait till is out.