They are lvl 75 iirc or thereabouts, whit to me at 77so that's a hefty range. They are basically a mini RB. I'm not a class that draws agro a lot so no idea about damage but from what it looked like he hits like an RB too. The main difference is that they have relatively low HP for a raid boss. How manydepends on how many people you have in there. When we did he him on lionna we took about 100 each time maybe 120. That resulted in hm spawning one ever 5 min or so. The more people you have the more often he spawns them and i don't know if there's a max number of them because we killed it within a minute of it coming out every time.
As far as i understood from reading it killing those minions should also grant stuff that will help in the raid, got any idea what that stuff was Physics4Ever?