I've played waaay too much Pokémon, so I like to think I have a good idea of which ones need a little help, and what they need to stand out more (or at least be useful a little longer; can't make Mightyena on par with Garchomp without breaking things). Generally I try to make changes that make some sense, or fit in with the mon's theme - no Flamethrower Butterfrees or Multiscale on things that don't have scales.
As a general rule I don't nerf things unless they're something I buffed too much, so everything will be at least as good as it is in vanilla games. There's a lot of stuff that should be nerfed in vanilla, but I won't do it in IE.
Yep lots of gen 8 mons will be getting buffed. Eldegoss, Boltund and Grapploct to name a few.
There are lots of sets that Altaria and Golurk can run, the best set for each depends on what your team needs.