3rd Gen Pokemon Emerald Team Help

Hey everyone. I'm doing a playthrough of Pokemon Emerald and I think I have an idea for my final team. Here is my idea:
Swampert (Water/Ground)
Manectric (Electric)
Shiftry (Grass/Dark)
Gardevoir (Psychic)
Swellow (Normal/Flying)
Hariyama (Fighting)

This is what im thinking of for my playthrough team. If anyone sees any problems with it or thinks i can change out one pokemon with another, tell me. Otherwise i think I know the movesets that I want.

Looks good to me! Visually, the colours are nice and diverse, that's what I always look out for in my teams.

If you're going to have these with you all the time, make sure they cover all your HM needs. In order for none of them to be overrun with HM moves, I suggest, beside the obvious - Swellow for Fly, Cut on Shiftry, Rock Smash on Hariyama - that you teach Surf to Hariyama. It gives it a strong, unusual move and takes that burden off of Swampert, which could do well with Waterfall and Dive. Manectric can learn Strength, which is decently strong and would do it good. You can teach Flash to Ralts if you need it.

Dig is very useful too, Hariyama and Shiftry can learn it. If you want a secret base, anything can learn Secret Power so make your pick.

I see you have all Gyms accounted for, Shiftry should help you tremendously against Tate and Liza. This team should get you through anything with no problem (but do teach them Ice-type moves when you go fight Drake).

Good luck with finding Seedot and Ralts quickly - as a Ruby player, I see Seedot as ridiculously rare in Emerald!