You need a fire control, for sure, as my own attempts revealed that they do need a FC of some type. I don't think it needs to be of appropriate range, I was able to shoot missiles outside of my range, but I haven't looked much into it so don't quote me on that.
I'd also point out that you definately want an active sensor on the drone, or else you're not going to see anything, and the weapon will strike towards whatever it finds, so it won't be a standing sensor buoy. I'm not sure... you -may- be able to load a buoy as a secondary ordinance, set to deploy at 0km so that it'll deploy a buoy when it reaches the target location. I somewhat doubt that this would work, however it's worth a try.