Can you hire more than 8 heroes in VIB?

Added 5 minutes later
PReDS, I won't burden anyone if that's what you're worried about. I'm just curious – is it even possible? And how much effort would it take.

I know at least 2 people who mastered ERM to a good level in six months – so, by putting in some effort, you'll find the answer to your question by summer and won't have to rely on someone else's opinion.
And in general: the reason why the Inferno patch is called that, and not Necro-Inferno patch, is because Vic couldn't come up with a reasonable algorithm to determine the boundaries of the Necropolis respawn area in the dungeon (at least at the time of our conversation on this topic).