Hawkflyer, Welcome to the forum. Some short answers for now....
RE your strange sensations down there: I have had what I call 'knitting pains' for the full 8 months since surgery. Not all the time, but it feels like something is just inside, pinching me. I am hoping that's nerves regenerating. To have a variety of sensations 3 weeks after surgery isn't unusual and even to be expected. Things are adjusting, settling, healing and such, so it will take a while to get it all sorted out. Give it a couple months to settle down.
The urine stream: It's still soon after removal of catheter and it takes a while for the swelling to go down internally, from the urether all the way to the bladder. If it doesn't improve shortly, or if you show any sign of infection or stoppage, see you doctor and get his opinion...In any case discuss it with him when you get back for a checkup.
Orgasm without erection: That's something else, isn't it. Just goes to show you ain't dead yet...lol Yes , that's a fact of life after surgery, you can have dry orgasms with a flaccid penis. No harm from it, and it's even good therepy for regenerating nerve healing, so don't worry about it. If it doesn't hurt, then it should be ok. If you wish, you can wait a couple weeks and try again. If your worry about getting excited is about damaging something, don't worry about it. If its the mental part of frustration of being excited and no erection, then there's a variety of ways left to keep intimacy and satisfaction for you and your wife going. There lots of other ways to achieve it, without the erection. The less you worry about it, the greater the possibility of faster recovery.
It's a long and emotional journey back for most of us guys, so join the club, we're all in it together now.