1. Top nut squeeze screw: Soak it in plusgas a day before. Then undo with screwdriver. Came out easily, although on the Ocean all the parts are stainless, not aluminium, which might've been why. The actual top nut was more difficult. Didn't have the right tool, but two screwdrivers stuck in the holes with a long lever between them did the job. Better to get the right tool though, doesn't cost much. Someone linked it somewhere around here recently.
3. Rudder position sensor: Jup, remove hose clips, remove sensor tang. No need to mark position, you wil need to recalibrate the center anyways afterwards. On reinstallation, with the rudder centered, the RPS should be approximately at center of travel too.
4. Quadrant: No need to mark, upon reassembly the frame dictates the height where it needs to sit (so it won't rub on top or bottom of frame). Yes, there is a key which you should try and not drop
The bolts that clamp it want some Plusgas prep too. I used the opportunity to alu etch prime and repaint the quadrant with black Hammerite, as ours was pretty yucky from a rusting Eberspaecher heater above it.
5-6. Rudder dropping: Make sure you have enough space under the boat for the whole length to come out. I think on the AC version this works? On the Ocean this is a real problem (because of the much longer shaft) and we had to use the travel lift to crank the boat as high as it goes to get the rudder post out and clear of the hull. Alternatively you can dig a hole, but the yard wasn't having it. Think your shaft is shorter and should clear the hull as is, but do measure (you have the rudder drawing).
Then just put a boatyard wood block and some wedges underneath, undo the nut and don't let the rudder fall. Yours is probably also much lighter with the aluminium shaft. Ours needed three burly guys to manhandle (in is trickier than out as it also needs to be aligned), but by then you'll have plenty of boatyard mates to help :)4
Old bearings: If they still turn, sure, you can try that. Most I've seen had to be cut out. Very carefully so as not to further damage the housing, make two cuts through one side of the ball where the housing is indented. Space them as wide as your favorite sharp wood chisel, then chisel out the plastic between the cuts. All very carefully. Once the ball is split, it'll come out easy.
Housing repair: I used International Watertite (underwater epoxy), because I had some leftover and it was great. Make sure you get it right and when you get the new bearing it goes in smoooooooth. Some idiot paid for another bearing because he didn't prep the housing well enough and it got stuck and had to be destructively removed. Ahem.
Reinstalling rudder: Definitely don't lower the boat onto the rudder. We just used the burly guys again, shoved the rudder into the boat, then used a lot of "starboard no the other way forward no back on your end yes up now hold it there!" and quickly spun the top nut on a few threads. Then wooden block + wedge again to lift it the rest of the way and tighten the top nut. Note that the top nut isn't necessarily tightened all the way.
Then hurry up with reattaching the quadrant and steering cables so you can be immediately launched into the water while you're already in the lift, without getting charged a second time for a travel lift movement, like some sad boatyard managers would otherwise do
Fine tuning you can do later, which involves centering the rudder with the emergency tiller, centering the wheel to match (by adjusting the bolts on the cable ends), making sure the rudder can still turn both extremes and is stopped by the quadrant frame and not the hull, setting up the quadrant height perfectly and reinstalling the rudder position sensor and recalibrating the autopilot.
Also, I've changed the large lip seal at the top of the tube around the shaft. Won't have that opportunity again soon, so might as well.
Good luck!