Firstly yes, The Hivemind is a must-have for all multiboxers as it allows us to get around so easily through doodads, phase lines (yes!) and a few other travel concerns like FPS and latency. It's also not terribly difficult to do and is well worth the effort.

Secondly your second group is going to be tops. Aside from running a whole tank group anyway. The mobility of BM and MW cannot be overlooked. I screwed up in the beginning choosing RSHM + 3 LOCK. Probably the worst possible combination for M+ having zero mobility. I'm currently working on a 2nd team of varied classes (WAR/PR/HNT/ROG/MAG). They're about 850 I think so going to be attempting some dungeon crawls on them soon. Thinking a more mobile and mixed melee team might do better than what I was doing before.

My last ditch team is going to be yours as I already have the DK at 390 and the MW and BM hunters are all hovering around 112. It won't take long to repeat their dominance of WoD content.

Still miffed that movement played such a huge role in BFA dungeons. Makes me wonder what 9.0 is going to be like. Mostly if Team A vs Team B belief is found to be true, 9.0 is going to return a lot of favor to stationary comps like Legion did.