Change the zombies health to somewhere in the region of 200 (or whatever 10 pistols shots is) and change the headshot damage to 200 (there are many threads on how to do this, use the search)
The animations are unique to that zombie unfortuantly.
Do you mean the image which appears when the player is hit or the enemies?
To change the players damage image, go to files\gamecore\huds\eyehud.dds(i think this is the right path) and replace that image with your one.
If you want to change the enemies, there is a way to do it but I can't remember right now :/
Migration Discussion Thread: http://forum.thegamecreators.com/?m=forum_view&t=142497&b=21
Piracy Discussion Thread:
http://forum.thegamecreators.com/?m=forum_view&t=142774&b=21