I did some more research and breloom will be the best in your team.Here is how I made breloom the best.
lotad - good early game
early mid evolution
late final evolution
seedot - no good moves
need to use tms
only good as hm slave
shroomish - fairly good early game
gets status moves
wide moveset after evo
After seeing all this and your team breloom will be the clear winner as an added bonus it will beat norman which would be difficult or else.I'll also give you the best nature and moveset.
breloom@miracle seed
nature-hasty or naive
moveset -
giga drain - nice healing move that deals solid damage
bulk up - nice set up so breloom can sweap
sky uppercut - strong move that gets stab
mach punch - always good to have priority move.