Protection from X does 4 things (with a useful acronym of "DEBT")
Damage - prevent all damage dealt by X
Enchanted or equipped - cant be done by X
Blocked - cant be blocked by X
Targeted - Cant be targeted by X
Exsanguinate does not do any of these, so runed halo does nothing.
Nope, it sure wont. Runed Halo gives you protection and protection does 4 things
It prevents Damage
It prevents Enchanting/equipping
It Prevents Blocking
It Prevents Targeting.
Exsanguinate does none of those 4 things. The main thing being is that it doesnt target. Each opponent loses X life. As stated before Loss of Life is not damage, so protection won't do ☺☺☺☺ against that either