Team 1: Really struggles with specially offensive mega altaria, as only klefki can switch into hyper voice when stealth rocks up, and it gets nailed by fire blast. A smart altaria player will be able to nibble away at the team pretty easily. Also, not a fan of manaphy set walled by the eon twins @_@.
Team 2: This is probably the team that I would enjoy playing the most, simply because it utilizes a lot of my favourite Ou pokemon. Sadly, it really stands no chance against dragon dance altaria, and really struggles to switch into earth power + knock off landorus. It can also have problems with opposing mega lopunny, ice punch mega metagross and some variants of tail glow manaphy. Its just not that great to blunt :(, but I really like the concept. I would vote for this if it were based off enjoyment purposes, but sadly, its not particularly useful in the current metagame. Mega Diancie also floors.
Team 3: Mega Manentric + Wobbufett seams to be a pretty popular core lately, but unfortunately, this team doesn't do it any justice. It really struggles to switch in to focus blast landorus and only has one good mega sableye check in manaphy as Ttar gets might get burned on a switch. Combine this with a lack of hazard removal and the team just gets polarized by Mega sableye hazard stacking teams. Defog skarmory or replacing wobbufet with something like the eon twins might help this case, but for now, this team doesn't seem to be that great.
Team 4:I actually find this one to be pretty decent (don't worry I'm British and "Decent" essentially means "good" when talking to others hailing from England). It does struggle to switch into HP ice landorus and special altaria (this seems to be a common reoccurrence with some of these) but the more offensive nature of team makes it less of problem. I'd honestly replace landorus-T with garchomp just to get a jump on opposing kyurem b and the fact that you have 3 win conditions means you won't be switching as often, so the ground immunity is less valuable, but then again, this may be somewhat biased due to my hatred of landorus-t, or at the very least, you could change the lando set to a more offensive oriented one since the nature of team seems to be bulky offence. Also, you have zero Hydreigon switch ins, but hydreigon isn't that common, so you should be fine. Pretty good.
Team 5: Probably the most effective. Doesn't get floored so easily as some of the other ones, and while you do struggle to switch in to landorus, that can be said for every team that does not run Cresslia, Mega Latias and specially defensive Gyarados at the same time. I would be wary off Dragon dance altaria, since if you fail to keep stealth rock off the field you can't really rely on Talonflame, and hippowdon will often be softened from previously brawls. You could replace crunch with whirlwind if Altaria scares you. Overall, pretty good job, you'll be getting my vote :).
Team 6: I'm pretty sure this competition is based of making the most effective team, so the reference to Mastermind is irrelevant, though this team does look very similar and feel Masterminds build is more effective. Anyway, seems like opposing kyurem b carrying HP fire can be problematic, and swords dance talonflame can clean if landorus-T is weakened, but other then that it looks pretty solid. Nice work.
Team 7: Defog Mega Scizor ain't that great and my only suggestions would pretty much change the whole premises of the team, so yeah, I'll just leave it at that.
Anyway, I'll vote for team 5 because it seems like the most effective, however, team 6 and 4 also have potential. The other teams can all be made good with a few minor tweaks here and their except team 7, which while can be improved, the changes would result in a lot of replacements so the original idea might as well be scrapped. None of these are bad teams, and but some just get beaten by more threats and lack the synergy others do. Good job anyone :).