Well, it took several hours contorted in a locker to implement my unistrut puller, but in the end I prevailed! (the harmonic balancer puller was a no-go because I couldn't find short pusher screws.) I had to use 3 different length pusher bolts stepping up by 1/4" each time due to the limited clearance, and the damned thing fought me until the end! I am still feeling the pain from the extended contortion act I had to go through to get enough power to the wrenches!
Here is a better look at the puller and the defeated coupler! Note the hard earned celebratory beer!
The Cutless bearing also gave me some trouble. The brass part of the bearing was so thin that getting a puller on it wasn't going to happen, so I took a hacksaw apart and reassembled it inside the bearing and cut it in several places. Even after being cut it didn't want to come out until I went at it with a pin punch and a cold chisel to get it peeling up. I pressed the new bearing in with a length of reddi rod and some fender washers on each end. Then it was just a question of winding it in. Initially I used 2 washers on each end. but they started going concave with the force it took, so I stacked 4 washers on each end! At least I know it's not going anywhere!
Hopefully that is the last time I have to do that job on the boat!