1. Vexamus: Tanks should aim Vexamus away from the group because Arcane Expulsion is a magic attack that can't be avoided. Healers and DPS should drop Mana Bombs slightly away from your spot, they disappear every 3 waves. Healers should dispel oversurge if DPS can soak more orbs. DPS should help to soak the Arcane Orbs if you have no stacks of oversurge.
2. Crawth: Pick up the balls when Play Ball! activates. Run over the balls to pick them up, and use the special ability button to throw it once you've arrived at the goal spot. Try to stay spread out but close to the boss. Don't attack when Crawth casts Deafening screech because you will be school-locked for 6 seconds. If Crawth faces you, sidestep away from his Overpowering Gust.
3. Overgrown Ancient: This boss casts his abilities in this sequence (Germinate, Branch Out, Germinate, Burst Forth). Healers must use healer cooldowns for the Burst Forths, and also pre-heal and time their heals-over-time before each Burst Forth.
4. Echo of Doragosa: Lure Echo of Doragosa away from Arcane Rift but not too far away from people. Healers should dispel the Energy Bomb when it is away from other people, it has to be dispelled quickly or else Power Vacuum will be cast after Energy Bomb. DPS need to move away from people who have Energy Bomb because if you don't move away then the Power Vacuum will damage everyone who's too close.
Happy dungeoning! ~ Keyboard Gatekeeper