Urgoz HM with 7 heros?

And for Urgoz himself, heros won't run around dodging the growths... could I flag them at the entrance and run around myself waiting for EoE to do its work? One player spawning growths isn't likely going to be enough to take it down, due to regeneration.

With only one playing character it may be a bit tricky if you're not a Ranger or a Necromancer I guess, as I'm not sure how precise you can be when it comes to placing EoE with heroes (close enough to affect Urgoz but without triggering a growth spawn while placing the spirit).

Mind that I did it in NM, and using two accounts before the seven heroes update (which shouldn't be much relevant, higher precision on characters placement aside, unless you want to do it as a non Ranger or Necromancer), but hopefully it may still be of some use:

What I did has been to place EoE then make an initial rush with all heroes to bring Urgoz (significantly) under 90%, making sure heroes are target locked, eventually with the opening cast selected (global flag heroes -> click on skills you want them to use first -> unflag when ready to attack) and any useless skill they may be tempted to cast anyway disabled. An Essence of Celerity can help a lot, maybe throw in an appropriate summoning stone too if you have one to spare.

Run around and eventually flag heroes to prevent them from remaining too long in the same place, but they're likely going to die anyway: the rest of the party just need to last long enough to have Urgoz significantly under 90% health (you need enough fire power to take it under 90% as soon as possible for EoE to start working and bring its health further down).

When Urgoz is low enough on health (or your damage dealing heroes are dead), flag all your heroes well behind the EoE Spirit (safe area) while running back to safety yourself, recast EoE if needed then resurrect any dead heroes (ideally with Resurrection Scrolls, pretty fast especially if they're all close enough to each other).
They should automatically run back to safety (as they're flagged), even if they may not make it in one run, and therefore require additional resurrections. This is why you need Urgoz well under 90%, in order to be sure that EoE will still work in the next phase.

Now flag 3-4 heroes behind the pillar which is between the EoE spirit and Urgoz, and of the remaining heroes place those with a resurrection skill close enough to the spawn-triggers to be able to resurrect them while remaining in the safe, no-spawn zone.

Your task is to maintain EoE up, between each summon you can run in for additional spawns and eventually long-range attacks, just be careful not to die.
The heroes will spawn growths, die on explosions but will be resurrected by the other heroes.

This is enough to take it down in NM: I had three heroes flagged to trigger spawns and me running back and forth in the spawn zone with the occasional crappy ranger attack and that was enough to beat Urgoz regeneration.

In HM I don't know if Urgoz regeneration increases, and the initial part of taking it down on health may become harder...