just made a new 3v3 team, and we want to have a few diff champs each to use so we cant get banned out, we play 1 top 2 bot, (even though i keep telling them bot is safer to solo lane) and we dont run a jungler yet, so right now solo top uses mostly sion, our support/roamer always uses volibear if thats banned he used syyvana, and i started out as APC, early games we wrecked, late, i got melted and we lost hard, so i switched to xin, and we got our wins back, what do i do when xin gets banned or picked?
our comp already relies so heavily on getting sion and bear, who do i need to use to help with that stun, flip, melt, chase the rest strat

and im fast approaching 6300, is fizz usable on 3v3 competitively, or should i get jayce for the poke n peel?

edit adding mains for our players

top: jax, sion, chogath
support/roamer: bear, shyv
me (i guess i try to fill the carry/assassin role) darius, xin, akali (find akali to be ineffective later in the game when she is needed the most, need to trade her, also darius is banned most games, so i need a better fit there also, and what combos of these champs do you think work best together?

so far our best results were jax, xin, bear, but the other team that game had a draven, and it was all too easy to catch him slipping

Jax could be swapped in for Xin. He has a jump in and a stun which can be similar to the Xin dash and knockup.

Consider J4..

Have you looked at Thresh? Build AD and Sorcerer's shoes and max Q first for the passive.

You end up with a high damage magic burst on the first attack and the sustained DPS of an ADC. Well not quite that good, slow attack speed, but he's the next best thing.

I've had luck with 15/15/0 so I'm not building glass cannon. Sorcerer's shoes, BotRK, IE, BC

And there is all the utility he brings, a pull, a gap closer, Dark Passage, a knockin/knockback, and (2) slows. Of course to get full use, your team has to get use to Dark Passage. That takes work.

Cassiopeia is a really strong underestimated choice, him and Brand.

Vi is similar due to her charge and knock ups. I play her like an off tank on 3v3 when the team needs someone who can take a beating and give it back to them.

If not Irelia is my other choice. She doesn't really have a stun. Her E is kinda weird. It is based off of health. Depending on the health it will either stun or slow. Though her CC is random it's her Blade Dash and Hilten Style that make her nasty. Turn on Hilten Style before dashing in and murder them with Hilten Style's True Damage. If you add in something like Wit's End you will add True Damage and Magic damage to your attacks.

I would strongly recommend going 1 top 1 bot 1 jungler. Once we got past silver to golds we have yet to see 1 team not use a jungler being succesful. I would say that 9/10 teams use a jungler, if not more.

Supporting just doesnt really work since that guy will have 0 farm and 0 items. The only "support" we have run into is something like a kayle and zilean teamed with a tryndamere or poppy.. All we had to do was pick something that seperates them and gg. Jarvin does that job perfectly. CC and beef really works.

We typically try to go something with good cc in jungle and 2 strong solos. Our bot is like a Vi, Jax, Renekton. Our top is usually Brand, Kass, Kayle. Our jungler is mostly Jarvin or Cho. Vi ulting into their strong carry, j4 ults in, brand ults, team melted, gg.

Anyways, GL.

Renek JAx Jayce and Vi can all be replacements to xin

For bot lane, APC's i can suggest are Annie and Mordekaiser.

Annie is great for 3v3. She is slightly tankier than most APs. Her spammable AoE stuns, which, since its 3v3, is likely to get the whole team. Bear pet can be used to initiate tower dives. At level 6, she can instakill most champions with a full combo. Only con is that she falls off slightly lategame to autoattackers, that is if your opponents can last til lategame.

Mordekaiser is squishy early game. He has no CC and requires Spellvamp. However, he has good damage and a game changing Ultimate, turns 3v3's into 2v4's. Once he gets to mid game and has Hextech Gunblade and at least one health item, he is next to unstoppable. My only suggestion is that you get 6% Spellvamp with runes and 3% Spellvamp in masteries 19/0/11 for an early 9% SV which combined with and early Hextech revolver is 21% spellvamp for only 1200 gold.