1. You can batch sparge, fly sparge or no sparge with a RIMS. I prefer to fly sparge, but I cannot definitively say that any one of these is superior to the other. No need to worry about disturbing the grain bed IMO. You can easily vorlaugh for a few minutes to reset the grain bed. It's not a big deal at all.
2. Yes, but again, vorlaughing is not a big deal at all, and especially so if you are pumping the wort anyway. The wort will clean in a couple of minutes in most cases. Wort clarity has little to do with the clarity of the finished beer. Mostly you just want to keep large particulates (grain husk particles) out of the boil kettle and that's easy enough to do.
3. 3. No, you are not forgetting anything. IMO, you have a good grip on what's going on. I also think that it may be true that a no sparge method may produce a higher quality wort. I've never tried it, so I cannot speak from experience. You are also correct that the additional cost, or reduced efficiency, is not a big deal and it may be worth the trade off. I plan to try it someday, but I'm getting good results with my present method, so I'm not in a big hurry to do so.
4. Running the pump then draining and refilling as you described will work just fine.
I see nothing wrong with any of the methods you have in mind. Do some experimentation with the various methods. Keep good notes and post back with your results. Should be interesting for many of us.