IIRC 88-89 and 90-91 hoods are different. Im not 100% sure but theres something different with them I THINK. Search around on the internet.

Another common problem is where the hood shuts, on the core support, it gets worn out and that piece of metal is kinda flimsy. There is a 10mm bolt that holds the lock in where the hood latches, loosen it and move it up or down till you can close the hood, You can adjust it that way.

The auto trans lockup code can be anything from a simple sensor to an ECU problem. If the car drives fine i wouldnt worry about it.

If you need 5 speed swap parts then your best bet is look through the classifieds here on IA and Craigslist. youll need

5 Speed Tranny
5 Speed Clutch and flywheel
Clutch Pedal
Clutch Slave cylinder and master cylinder
Clutch Lines
Shift linkage
Axles
ECU