Welcome to the forum!
1. If it's stock it has no locking diffs.
2. Yes, Sailcloth is that much better, Bestop makes the factory tops and if your hardware is still in good shape then I'd recommend the sailcloth replace a top, they really are the best.
3. Zipper lube, candle wax, or soap are all good for sticky zippers.
4. Sport package gets the 4.0L I6, upgraded wheels and tires... Idk, what else or even if those are accurate. I have an '01 sport and it has tons of stuff, but my PO ordered it set up the way he wanted it, so I can't say what he ordered extra and what came stock.
Someone who knows better than me will chime in soon I'm sure!
Don't forget to wave!