I'm no doctor, so please take what I'm about to say with a large grain of salt, but.
I would imagine that it is possible for partial paraplegics to have erectile function and/or bladder/bowel control. If they're a paraplegic because their spinal cord was cut, it all just depends on where and how completely that cord was cut. If it's a partial, or between certain vertebrae, I imagine the legs could go out without the sort of pelvic area being affected.
The caveat being that I don't recall from my anatomy classes just which of those big main nerves insert where down there. If the ones that control the legs are higher up than the ones that control the bowels, etc., then it would be impossible. But generally things are in order, so you'd think the pelvic region would be controlled by nerves that attach to the spinal cord higher up than the ones that control the legs.
I'll bet you'd be able to find a diagram online that shows the spinal cord and the big nerves, and which show which nerve controls what. I know there was one in my anatomy textbook. Then you just take a line and slash it where you want. Everything above the line works, everything below doesn't.
I don't know enough about the other stuff you asked about to even make a guess, though. Good luck!