EVs are now added before Experience, so if the victorious Pokémon gains enough Experience to level up, its new stats when displayed in battle include the new EVs.
I think so ;o
Anyway, the stat increase is lower at the earlier levels, so you'll only be able to see the full results at level 100. I wouldn't be worrying too much about your Beldum right now. Additionally, your stats are also affected by IVs. If you have bad attack IV on Beldum it isn't going to go up as much as it would if you had a good attack IV