Be very alert during fighting trash. I personally found trash much worse than bosses! If your tank isn't well geared or your heals aren't too strong it might be better to not pull too many aevis at the same time.

First boss is fairly simple, do your usual thing but when he runs off run *with* him and stay behind him.
Second gets really hectic at the end, tornadoes are unleashed and if people don't stay out of their way they get debuffs which eat their HP. So esuna everyone and heal them and try your best to avoid being hit by those. (I found best position is middle part of the room but as far away as possible, you can see there where tornadoes are and can dodge them quickly and focus on healing). Its always good to have a range player handle the cannons, its just faster instead of running back and forth between boss and canons.
Final boss can be tricky only if people don't dodge. Just keep an eye on floor colors (anything that isn't colored naturally is bad XD) and esuna people whenever its needed.

All in all its a fun dungeon, not gonna lie I failed it the first time but that was mainly because we didn't handle trash well.

Good luck!