Frenzy / Dauntless question, plus others

Hi all. Had my first league game. Great fun. A couple of questions occurred to me though as I encountered some new rules.

Dauntless requires a roll to see if the strength matching takes effect on a block. In the case of Frenzy where multiple blocks may happen, is that roll made separately for each block, or just once for the whole activation?

A couple of other simple ones: If you use a team re-roll on a block with 2 or 3 dice, can you roll them all, or just one die?

Finally, (now I've got some winnings to spend) what purpose do dedicated fans and cheerleaders serve? I gather fans are just reflected in more winnings per game?

Thanks all