R Commit, discard 1 momentum: After you completely block your opponent's attack, play 1 Reversal with a printed difficulty of 4 or less (no control check necessary).

2 questions. First,  does this ability replace the reversal I would normally play for blocking an attack?

Second, am I able to react with more than one of these to a single attack that was blocked completely?

It just says to play 1 reversal, it doesn't say anything about playing the attack "AS a reversal", so it doesn't replace your actual Reversal during the Reversal Step, and you may respond with as many Peaceful Way as you want to one block.

Note that the Peaceful Way responds to the block itself, so any Peaceful Ways you want to use come before actually playing an attack as a Reversal during the Reversal Step.

After the opponent's blocked attack resolves, you proceed to resolve any attacks you've just played (via peaceful way and/or reversals) in the order you played them.

So by that logic, I should be able to react with The Peaceful Way and then react with Know When to Talk without any problems.

Know When to Talk....  R Commit:After you block your opponent's attack, each player adds the top card of their deck to their card pool face down. You may not play an attack as a reversal to this attack.

Yup.  :)  That'll work.