1) I think they jus mean foresight, it's either near 100% or 100% activation on next swing on you, featherfoot is not as high of a chance to activate though.

2) One piece of gear with HP materia is not really worthwhile, but stacked on 4 pieces it will help you eat 100 tonnze much better than other stats. Really only need HP gear for coincounter if you're straigt tanking...

3) I've solo healed a war tank straight tanking coincounter that used HP gear, and had no problem doing so. War tank does not mean you need 2 healers lol.