I fought those two several times, and it never happens the same way somewhy.
First time using a pretty powerful fighter i waltzed to one, deaded him, went to the second and croaked him too, both stayed dead, and i discovered later the loot at the bottom of the screen. Nothing more.
Second time, using a monk with the huge sword, I easily dispatched one, but needed to uncover some tiles before fighting the next, and the first one revived after the second died. Gold did appear at the bottom of the area thought. I kept killing one after the other, and for every kill the other respawned, and i got some gold at the bottom. Went through something like 350ish gold like that. Which somehow feels quite like a glitch.
As for Dracul, I got him from a subdungeon in Eastern Tundra, but it seems he can show up in different other places. Just keep on resetting the dungeon every time it's not him and you'll get there eventually.