1) On the trash, The casters can be interrupted and their main cast you want to interrupt or stun is Flame wave. (They do a scorch to you, that you can interrupt, I usually make sure I either have kidney shot or kick available and interrupt this as much as i can, but priority is the Flame wave This ability does a knock back if the cast gets off and can end up pulling unwanted groups. Also if kick or stun are on cd blind will work to stop the cast. Especially, useful if you are out of range for kick or stun and a caster is about to cast it.

2) On the mini boss Saviana Ragefire Feint is nice for when she is doing her big aoe.
Also even better, it is great on Hailon when he is doing his aoe. With some much damage going on and especially in phase 3 when you have fewer healers cause the raid has to split into two different realms, feint is really nice to keep you alive and give the healers some help. Be nice to your healers.

3) Cloak of Shadows works to dispel the debuff you get from Hailon. I advise using sprint or rocket boots if you have them to sprint far out from the raid to the wall of the dome to drop the debuff when you can. That way you can get it away from the raid as much as possible.

All the trash is stunnable and can be disarm, except for the elites that lead to Zarithrian they cannot be stun .