BFA is poison heavy. In that you want a poison cleanse, for sure. Freehold actually has mobs that stack a healing debuff on the tank which will kill if not dispelled. King's Rest has an ooze room where they shoot ooze on the ground every .5 seconds randomly targeting you. The only way to really deal with that room is to have a highly mobile comp to avoid the puddles.

M+ dungeons are mechanically complicated. Think Cata > WoD > BFA. BFA is in much the same design as WoD and Cata were. Lots of positioning and movement involved. One of the main reasons MDI was all melee.

I imagine your comp will have it easier than my initial caster heavy comp had it but be ready for some serious roadblocks. It's not Legion for sure.

Mechagon is absurd. That's the uber dungeon for BFA. Not boxer friendly at all. I can think of several encounters there that will make you hate multiboxing.

Might be better to just solo box some of that stuff but then it calls into question why you multibox at all. BFA is a tough expansion to love.