Alright, so you wanna know where Treecko, and Aron...I also, remember you saying something about Munchlax in your vid. I'll give you all three locations, okay?
Aron lives in Union Cave both floors (Day) Looks like you're gonna halfta go back inside if you want it. :p
Treecko also lives in Union Cave (Night) Floor 1 And Turtwig is on the same floor, it just comes out during the (Day)
Munchlax lives in a couple of routes: Route 36 (Day) Route 37 (Day)