Temp, coul you put a sub in for Mr. Bubbles saying this "if tyrantitar ever targets me, then taunt instead' just for a couple of rounds while a roost-chill back to decent health? Even if you just do it ever now and again that would be great.
MB, don't be worried about the boss. It's a Tyranitar. Ie 4x Fighting Weakness, 2x Grass weakness, 2x Steel weakness. Plus, Toxicroak (who will be drawing the most threat) resists both of its STABs and can Drain Punch for massive damage.
It should be a piece of cake.