Hmm, I personally have a breloom.. So trust me, he does not need drainpunch, he's not one to last long, but if you want it, then you should have poisonheal as an ability, but this will require you to drop the focus sash for a toxic orb and a move slot for substitute, you could get rid of stone edge since breloom is too slwo to outspeed any decent flying type anyway, besides they tend to be dual type: flying/normal, so you could just use spore, set up substitute and wear down the bird with a barrage of drain punches. I doubt you need any grass type moves since your team mates are all grass types, instead you could add leech seed or protect to stall, in order to regain any lost health. That is if you want a hard-to-kill breloom.
However, I know for a fact that effect spore will only get in the way of spore. You could accidentally end up paralyzing or poisoning the target, in which case you may waste a turn trying to spore the foe.
If you want a physical attacker, go with technician and keep the focus sash( this is what I personally would go for) or go with poison heal if you want a staller. If you raise his speed, you could outspeed andspore the overrated metagross to set up on him, but keep in mind that the sleep clause prohibits you from sporing more than one pokemon. Hope I actually helped this time.