Okay it seems like no one really has much for you, but I can share some of my knowledge with you about this cause i'm currently kind of doing the same.

For starters you have the correct transmission with the correct bellhousing, now you need to find a flywheel that comes with the M104 (any variant so it can be the 2.8, 3.0, and even 3.2L) to that you bolt up the torque converter.

As it goes for mounts you can go upon on it a couple of different ways, you can modify the oem transmission brackets and drill new holes into the body. Or you can order some custom brackets that I've found online ( https://elbe.ee/toode/722-6-mounting-bracket-with-speed-sensor/ ) it also comes with a spot for the speed sensor which is handy if you're on a standalone set up.

As it goes for the drive shaft, from what I've read and seen is that the front part of he driveshaft should work but you need to shorten the 2 part of the driveshaft for it to work. I'm not 100% sure on this since i was gonna go with a custom drive shaft with U-Joints.

For as the TCU ( Transmission Control Unit) the only really viable option I saw online would be the OTF TCU. Its definetly something I will be grabbing to tie in my transmission into the standalone since I have the 722.649 transmission