For Gardevoir a pretty good moveset would be Psychic/Thunderbolt (or Shock Wave)/Calm Mind and maybe something like Hypnosis (legendary catching, etc.) or Thief (if you want to steal some items). Shadow Ball is physical in gen 3, so it won't do you any good on it.
Swampert should probably run something like Surf/Earthquake plus something like Brick Break or Return or maybe Ice Beam. The main issue is just TMs not being usable more than once, so you won't be getting an optimal moveset for all your Pokemon.
I'd say that in terms of typing you could either put in a Fire type (like Camerupt) or a Fighting type (Breloom or Hariyama come to mind). Just keep in mind that Breloom has a terrible Special Attack, so its Grass attacks won't do much.
You also might wanna switch some things around for the HMs you need, because as it looks now, your Swampert's probably ending up as some sort of HM slave, because it's the only one capable of learning Dive and Waterfall.