Snorlax with ZH / HS

I would power this up. It seems like your chances of encountering one are pretty slim to none given your level and this being your first. The next one you catch/hatch could come in a few days or months and that's if it has worthy IVs for investment. Not as optimal as Body Slam, but that's a legacy move now and has been replaced by this. I would do it. Good thing you got Zen Headbutt too

Yes, power it up. Great IVs and the moveset is probably as good as you're gonna get right now.

I guess, Heavy Slam might be slightly better with the nice steel typing (useful vs Tyranitar) and 2 energy bars, but HB is still one hell of a charge move. So I would also recommend you putting some dust on it. :)

DeepChu, hatched Pokémon tops out at Level 20. Wild Pokemons top out at Level 30. FYI