Hi Gary,
I'm local. Call me when you have time. I will be available in the AM. 214-914-2446. Also, please look at
www.scatracks.org. The Shelby meet is at TMS on 10/28-30. You should join/attend if at all possible.
Regarding your specific questions....
Use synthetic transaxle fluid if you can. Something like Amsoil will be fine.
You can run the condensor up front if you like, not an easy job to relocate. May want to look for air leaks, and make sure it has been properly serviced. e.g., new receiver/dryer, proper evacuation, and proper charge (R-12 or CF-134A)
Vibration may be loose halfshaft bolts. They should be safetywired and loctited. May also be a warped or out of balance rotor. Is the transaxle properly mounted & snugged down?
The transaxles most folks use are geared that way... Mostly high HP 4 or 6 cylinders is what they came on from OEM use. Unless you go with a custom ZF ratio'ed box, ya just have to live with this one...