Also is it possible to get those 2 trophies as well as Mostly Flesh and Steel in one run? They didn't unlock on my 1st playthrough for some reason so I thought I might get these 3 done in the next run, but I'm worried it won't be very doable because of that bit with Granny Rags's key.
First of all, you should never NEED to kill hounds. They can either be avoided (prefered) or sleep darted. A sword will alert them to your presence and a pistol will alert everyone. Why use regular bolts when you can just sleep dart them?
It is *possible* to get these along with Mostly Flesh and Steel. It's just difficult without Blink level 2 and (to a lesser extent) possession and bend time.