Salahdin (a druid) recently wrote up a good guide for that spot, and I added it to the wiki here:
https://wiki.project1999.com/Earring_of_Essence_Guide. By all means please feel free to add to it if you have anything to contribute once you've spent more time there.
It doesn't address your specific question though. I know for sure that at level 60 you can single pull him, but I'm not sure how much lower you can go without agroing the rest. I
think 54 should be high enough, but of course keep gate memed and be ready to move in to a corner if they all agro.
As for a safe pull spot, Droga is pretty dense so not really. However you could clear the mobs outside to create a temporary safe pull spot. Honestly I'd recommend doing that anyway; once you kill the PH you have nothing to do for 20-odd minutes, so you may as well get some faction and loot from killing the other goblins in the area.
Also there are a couple of "mini-nameds" (goblin soothsayer and goblin fanatic) which can spawn in place of some of those other random goblins, and they can drop decent loot like the
Stone of Morid, so by killing the random ones you're actually killing (some) mini-named PHs.