1. Do mimics cast various spells from my skillbar or do the "mimic" me and cast same spells as me?
I think the first but have almost never used this helmet.
2. Does "firebat cloud of bats" work similar to the popular pre ros firebat?
Ie is attack speed irrelevant?
Sure it is nice to build up the full 850% fast and if I use taeguk I want the stacks but in regard to damage ...?
1)They cast selected spells from your skill bar. Not all of them
2) Not sure what you mean by similar?
Attack speed "ticks" faster, although animation speed will be the same. This is how Firebats staff works.