That small center bracket is all you need, just a few bolts and easy to get to. Good luck!
Back to the thread topic, I picked up a detent cable hold down screw at the hardware store, this is the one thing that went down without issue. Then hunted down a detent cable seal from NAPA which was too big and the only one they had listed. I had already set up a meet with a cool trans shop to pick up a detent cable actuator rod (that's in the pan) since that's not an auto parts store part so I asked him if he had a seal too and he did and it was the right one. It's a good time as any to crater a good afternoon so as I walked out to my car, the rod fell out of my wallet that I carefully placed there to be secure and I didn't realize it until I got home 20 min later UGH... I drove all the way back up there and found it sitting in the parking lot. alas, it was a wasted trip anyway because it was the wrong one too and was too long. (YES I know what a TH350 is). I tried to fabricate a shorter one out of it and did ok but it kept getting hung up and I didn't want to risk it so I said to hell with the auto kickdown, most of my cars when I was young never had them hooked up. So I installed it with the new correct seal and just left it not hooked up in the pan and finally I was ready to start it up. Put 4 Qt of tranny fluid just to start with until the converter filled up and of course the pan gasket leaks. I tightened it a bit more but it was a no go. It's a rubber gasket which I hate so I am picking up a cork one tomorrow, I knew I should have just replaced it from the get go but it was new and already there.
At any rate, I DID get to hear the starter engage the new flexplate and it sounds good and with the engine running I verified there were no "other" leaks so at least I kinda sorta got something accomplished. Tomorrow will be a standard pan gasket replacement.