I was wondering how I could run a Horror Campaign using Spycraft 2.0?
Sure! You'll want to start with
Fragile Minds, our cosmic horror expansion, which turns stress damage into a great vehicle for dread and terror in the game. It also contains several Mythos monsters.
Would it be possible to use the monsters from Fantasy Craft?
Mostly. There are quite a few differences between the games but the fundamentals are the same - and you can ask questions over in
License to Improvise when you get hung up.
Happy hunting, and Stay Crafty!