The Response on Curious Brandybuck puts it into play. Do I need to pay it's cost when doing so, and if not do I even need a Spirit Hero in play?

Nope, don't need to pay the cost and you don't need a spirit hero. The same goes for Elven Jeweler and Emery (although good luck playing her without any spirit heroes).

YAAASSSS....

He can be a super chump blocker for free when in need.