I explored all of Umar Hills, killed those Umber hulks, etc... but I haven't figured out where the wolves/werewolves or whatever they are, are staying

is it in the Temple Ruins?

any other tips for it would be appreciated as well

okay
the umar hills

first what you gotta do in order to get the quest rolling (after talking with minister lloyd) is look inside the ranger cabin

inside is the resident rangers journal and a 'note from mazzy'

one of them i forget which updates your map

go to the temple ruins and follow it from there

any tips for killing those shadows???

I've tried it 3 times in a row... still haven't managed to kill the shadows (at the temple... and I did turn on that light crystal), without losing several characters...

Stand in the area flooded by the light from the mirror. Anything entering the area will burn up. The shadows will stop showing up then you can venture down into the temple. (you must turn the mirror a couple of times until the light strikes it the right way... once you have it right you won't be able to turn it again).