Yep I forgot about the retaining circlip that goes in last to that slot, was there one when you started this marathon removal Dave?
Yes, there was one, all brown and red! I took it out immediately and plan to sand it down before I install it again.
Still having trouble with this other hex nut. I even bolted down a new vice into a sacrificial table to aid in the removal, but I'm having no luck! I even let the bolt sit in the tranny fluid/acetone for about half an hour. Here is my current set up, I'm feeling confident that after awhile it'll come out though.

I thought it was cool that I found this:

But...Believe it or not the "6mm" wrench didn't even fit into the bolt, like my OTHER 6mm hex wrench (the one in the first photo) I was pretty bummed about that. Makes me wonder about those other hex wrenches in that fancy set...I sure hope I can return that thing.

Edit: Quick question, I'm reading through the shop manual reassembly list, and it says, "Apply a coat of thread lock cement to the socket bolt and tighten it with a socket wrench."
This thread lock cement, probably not necessary right?