If I have a pet (A) and sick it on a target (B) can I tell A to "all follow me" and vet him, making him not attack, while someone tames B?

Or will it anger the beast?

It works wonders with Bake Kitsune. However, with anything that goes aggressive when you attempt to tame it, it isn't very effective since the tame will target you anyway.

Ah ok, so it won't stay targetted on the pet. Thanks!

It depends on the Mob, if it is one that gives, "You have angered ....." then that will give it an opportunity to retarget and YOU may be lunch.

On the other hand it may be such that if you beat the mob down to all Red and then just tell your pet to stop/follow etc, that the Mob may be so po'd at the pet that it wont retarget and even if it does, being beaten down so far generally means it moves so very slowly and the damage is so greatly reduced.