Do you have problems with the dodging bug (your Pokemon died although you dodged the attack)?
If you do, you should consider having some Gengars up one's sleeve, if Mewtu has Focus Blast, cause your Tyranitars will die instantly.
Otherwise this looks good, i fought with Gengar instead of Dragonite and got my +3 balls for damage.
Is this a good mew2 team?
All tyra have b/c, 3x 15atk 1x 14atk
Scizor 10a15d11s fc/xs
Drag 15a15d14s dt/or
Problem is that I dont know with how many players I will fight mew2. Right now I know there will be about 10 players 30+ but it is possible that there will be someone who is not on our chat for raids. If that happens it is possible that se will fight him in teams (inst, valor, mystic) so thats why I need all 6 mons as strongest as possible.
Note: I can power up those tyras who are not lvl 30 on that lvl. But only if you say it is must and I cant do reasonable dmg without them.
2nd note: I have those mons that I can add to my team: tyra lvl 20 15/11/15 b/c; gyarados lvl 25 14/15/15 b/c.
Thank you so much for your answers and advises!

Answers
If you care about your performance, powering up Tyranitars is the way to go. Against non-FB movesets it's just so much better than anything else and even against FB it's like fourth best, just becomes glass cannon instead of tank.
Tyranitar's Bite has a breakpoint at level 27 for 15 attack against Mewtwo. Since Bite has very low damage, that breakpoint is a huge deal and it's well worth it getting your Tyras to it.