I wish I could give insight on this as well, in previous expansions it would undoubtedly work. There has been a video of 5x hunter doing regular mythic, and I would assume this build is more stable than that. Just unsure on the scaling. It would come down to how well you can maneuver your additional team. They can avoid anything on the boss / aoe / cleaves, but having them dodge stuff while tanking may be the hardest part.

I do like the idea of the pets doing DPS while you are dodging stuff, it allows for a consistent source of damage when we usually are unable to do so.
I would also be interested in knowing what the pet dps contributes vs what the hunter does.