Congrats on your new toy!
#1. This all depends on what's on there now. The only way to know for sure, is to mike out the cylinders and see what size it is. Generally speaking, if it's a stock 1600, then only 1600cc or 1641cc jugs/pistons will fit without machining the case. Any size can fit with machine work.
#2. Again, it depends on the size you go with. The bigger the cylinder, the more air you'll need to feed it, so you'll have to go with larger valves to get enough air in and exhaust out.
#3. Sorry, I can't help on this one.
#4. "Type" refers to VW model:
Type 1 = Beetle and Ghia
Type 2 = Transporter (Bus, Van, Single Cab, Double Cab, etc.)
Type 3 = Squareback, Fastback, Notchback, etc.
Type 4 = 411, 412 models, only built between '68 and '74. (picture below) They were intended to be a "Luxury" model VW, but popularity never caught on.
