1. anything 96+ is obd2
2. see question 1
3. no matter what you do you will need lots of wirirng done...whether its obd1 or 2...converting to obd1 means an obd conversion harness and soldering new plugs to fit obd1 injectors and distributor....it will be eaiser to stick with obd2.
4. if you are goin all motor....might as well since it will cost quite a bit to put in 11:1 pistons and so on....basically if you can afford it without taking money away from other parts of the swap go for it.