I don't think this is the right thread for teams, seeing as how that's not a simple question. I offer you this advice:
Golbat + Eviolite = Wall
HP Fire in rain on things 4x weak = 240% (.6 *4) = 168 (assuming max damage HP)
HP Fire in rain on 2x weak = 120% = 84
HP Fighting (SE on thorn, if he is your main concern) in rain on 2x weak = 200% = 140
Magnezone does not resist water, so you're boosting your opponent's water attacks to kill magnezone (like a dragon with a water and fire attack).
Advice #3 Build a team, play on PO, figure out what is working and what isn't, fix said team, play more, fix, play more, fix and/or pos it in Rate my team at this point (not before) and give descriptions on what you think works, what you want to improve, but don't know how, how the team does overall.