So I know that weapons do a x% damage reflection on the incoming damage, I just want to understand:

Q1: In the bellow will the reflection apply on 1k damage or 500damage?
Boss doing ---1k damage--> [25% damage reduction elixir on player] + [armor] ---500damage--> Player.

Q2: Mephisto reduces enemy damage by 15%, so:
a) Will it affect my reflection damage if my opponent use it on me in pvp.
b) Will it affect my reflection damage if I use it on the enemy.

Thanks.