Pardon my ignorance, but is that 3 fingered drive coupler looking thing for the front diff on an AWD and it it direct coupled to the internal diff for the rear wheels? If so, is there some sort of viscous coupling to the front tires to allow the longer travel radius in a turn?
I applaud your bravery digging into this yourself. When I was a young man, a neighbor convinced me I could rebuild my own torqueflight 904. "just pull it and I'll come over and tear it down with you. In 20 minutes he had it scattered across the garage floor saying "yea, this is worn, this needs replaced, this too. Just get a master rebuild kit and a rebuilt torque converter and you're good to go" After playing with it and looking at the service manual, I had it back together in an afternoon, and not $800 poorer.
As long as there are no selective shims associated with part tolerances, you should be able to get this handled yourself. Get at least a decent dial caliper and verify the new parts are the same thickness and you should be good.
Beware, this advice is only worth 1/2 what you paid for it.