#1 No since they were OEM copies and already used technically you cant use them.
#2. Windows Vista: Home Page
The Vista website. It has all the info you need to knwo about each version.
#3. 32 Bit vs 64 Bit - Google Search
Google search on the difference between 32 Bit and 64Bit. If you dont have 64 bit you cant run it. So find that out first.
#4. Retail is the copy you buy in store. OEM is the kind sold to Dell and HP to be used on their PC's. Retail has 3 activations for Vista while OEM has 1 activation for VIsta.
#5. If it is OEM no. But if it is OEM then the answer to #1 already applies.