Scion RF Ascendancy. Info needed :)

i started to play an RF Scion(legacy) and i'm thinking about ascedancy classes. ive got couple question about:

1)Elementalist - reduced 4% elemental damage taken - will it decrease the damage im taking from RF? and if yes how it would be calculated (lets assume ive got 1,000 hp, 75% fire resist and elemementalist)?

2)Inquisitor - will the reduction work in the same way (the same mechanics when it will kick in) as Elementalist? and second question - from description it will regenerate 4% of max hp. From youtube vids the bonus is boosted almost 2x (so almost doubles the life regen) what do i miss?

3)cheftian - it gives teh chance to ignite. Do RF can ignite? and second one - it got 10% chance of gain endurance when hit. if i will have CWDT what will proc first (assuming ive got 0 endurance charges and after hit i will get one CWDT's skills will be considered as cast with 0 or 1 charge) ?

4)Trickster - how is considered 0 energy shield? if i will have 0 ES will "20% increase damage when not on a full shield" be turned on or of? and second one - just to make sure RF is not a dot, so it will not proc the "30% recovery rate when killed a mob affected by dot"?

and a side question: will RF trigger Decay?

Trickster would be core. When your ES reaches 0 at the start of the map or zone due to RF your damage will increase. RF is a DOT. It doesn't have a duration tag so stuff like Rapid Decay won't effect it. The increased recovery helps tremendously when you're clearing, but it can be hard to sustain. You want to avoid backtracking and prolonged boss fights as much as possible.

I picked Pathfinder as second, but I guess you could pick Elementalist and maybe use a Flame Golem just to do it. Pathfinder provides way more benefit while clearing because you'll get more uptime for Witchfire and other flasks. The reduced damage taken stuff is part of the formula found on the wiki for RF.

Inquisitor stuff only helps if you're standing on consecrated ground. Pretty sure the 15% chance to ignite from Chieftain is for hits. RF doesn't hit so it won't trigger that or Decay from a Delirium weapon if that's what you meant.

Experience: Respec'd a Scion to RF to test & mess around. Did a bunch of Shaped Mesa's while testing. Assuming we're talking about a life based RF because anything else would be just no.