Attunement Question

Hello Everyone,

I'm at work right now and haven't tried it, but just before I left for work, I beat Thunderhead Keep (wow, what a marvel considering the PUGs these days, <end digression>). When I got to RoF, I managed to get into a group looking for skill capping. I was fortunate enough to capture the skill "Elemental Attunement." My questions:

(1) Is this a skill worth using?
(1a) If so, is it good in PvP?
(1b) If not, why?
(2) Can the Elemental Attunement be stack with Air/Fire/Water/Earth Attunement such that the cost of the spell is reduced by 80%?
(2a) If so, is this a bug that is going to be fixed?
(2b) Does anyone recommend using two skill slots to achieve this?

And in continuance with my propencity to digress from my Thread subjects, but, for the sake of not consuming more space in the SQL database:
(3) What is the most effective Element against the minions/foes in Perdition Rock, more generally, in Ring of Fire. I assume by implication that the Ring of Fire consists of fire-resistant creatures, but my Fire Nukes seemed to be fairly affective (in comparison against foes in Shiverpeaks.)

Thank you for responses,
zehly.