On the Drow that were killed by the Orc's it was all the Drow that were with that part of the army.
Which was the leftover of the contingent send by the new drow city, after all drow send by Menzo have already left.
Not quite. It was a Wizard and they managed to trick the clerics of Gruumsh using illusion magic.
No, they tricked the frost giants using fake clones of the "brothers of Thrym" (and that Thrym didn't give his clerics the slightest hint that something was off, it only shows how in Salvatore's novel Lolth is the only deity that get things running, with some occasional nod to the dwarven deities and Mielikki).
Drow clerics and even fighters direclty intimidated high ranking orc clerics on several occasions. Oh how I would have loved to read them actually messing with the wrong orc and being faced with a high priestress of Luthic, as powerful and nasty as an matron mother. But Salvatore would have none of that.
An entire kingdom of hundred thousand orcs and more and among them not a single high level orc the drow took more than semi-seriously. You know, because drow are just uber and the orcs are entirely fodder for them
Hartusk was not their greatest warrior ether he was just the War chief
It was stated that Hartusk was one of the best, if not the best, fighter in the entire orc kingdom, which is the reason why he became a powerful warchief before the orcs decided to make him king.
The ease whith which the drow were able to stage their game of orc thrones tells all regarding how Salavtore rates the two kingdoms. The orcs could not even muster the least bit of resistance to the drow just arranging their rulers however they needed.
Which was only a part of the army the entire Orc army was in that small area.
Against an even smaller number of drow, which they outnumbered by a vast degree.
It was not stated if the Orc's took any losses and it was implied to have been a one sided slaughter likely due to the Drow not expecting it.
I have to reread, but I am pretty sure the heavy losses were stated. Also the drow were expecting it, as they were trying to sneak out of the camp because they wanted to abandon the orcs before the noticed and knew they would have to fight their way out if their stealth failed them.