So the ability says after the 6th card into your card pool. What if I had discarded some cards from my card pool prior? Say with Whirlwind I discarded 3 cards from my card pool, can I just play 3 more to trigger the response?

No. It's the 6th card in your card pool not the 6th card played this turn.

Yep. Multiple something out, then spam a couple of foundations...it works nicely off of Air =D

All it cares is how many cards are in the pool when you turn it sideways. Well, that, and that the sixth card in the pool was played, and not a multiple copy =/