You do not need a computer to control the 700. It wouldn't know what to do with it. On emission controlled vehicles, the vehicle's computer ONLY controlled TCC (torque converter control), which is only an on/off function. This can be easily configured for automatic or auto/manual function.

You will not need the updated pump. The 1990 model should already have it. You will need the Diesel spec governor. You should use the low stall TC, but it is not absolutely necessary. I recommend it, but I know of a bunch of them that are using a gasser TC. With the higher stall converter, you will give up a lot of the low RPM torque, economy will suffer a little (all that fuel to wind it up is not needed to get going), your "effective operating range" will be reduced, as the redline on the Diesel comes in a lot quicker, and if towing, it will generate a lot more heat at lower speeds. If all you are using it for is a high-geared grocery-getter, the gasser TC may be fine.

The Trans-Go shift kit is HIGHLY recommended, as a starting point. If you have the thing scattered on the bench, you might as well add in some other "near bullet proof" hard parts. Otherwise, drive it sanely and save up or collect the parts along the way. Don't be fooled by the "I'm only running it behind a 6.2L so I don't need much" idea. Many times more 700's have been killed behind a 6.2L Diesel than much higher production, high-performance SBC's.