2. The stock hard lines have nice bends where they come out and run parallel to the frame. You can cut those off and flare the ends to an AN fitting and get AN soft (or hard) lines to reach where you need to go.
3. The fitting in the transmission and the radiator will unscrew because they are NPT inserts. You can remove those and replace them with whatever NPT fittings you like.
Personally, I like to go with Option #2. The stock hardlines are nice and tight and it is really convenient to be able to quickly disconnect them.
The suspension question is more complicated. Let me think on that one a bit. Autozone will loan you a compressor tool. I have seen a few lowering kits for that vintage truck that might work, but let me cross-reference the van 3500 against the other availavle suspension types before I lead you down the wrong path.
