1. Snow Leopard is the newest, but Leopard runs just fine as well and probably has slightly better support at the moment.
2. You don't "need" 2GB of ram, but its a cheap upgrade and will help system performance a bit.
3. The 8GB SSD will take an OSX install but you'll likely need to strip things down a bit, and you won't have much room left for much else.
4. I would go here for the step by steps of getting it working.
Guides | OS X | mechdrew