So, if I use my stones will I get the loot?
Just killed one of those guys with 4 other people and only one could loot and get a key for the solo scenario. We couldn't even roll.
Is it random or is the player who summons the mob the only one who can get something?
No. It's random. There were four of us in my group last night when I summoned it.
I (summoner) got nothing.
2 of the others got a key each.
The last non-summoner got nothing.
None of the keys were rolled on.
So, you can blow your key and get nothing at all from it.