1.) Just get a Pro. Premium does not come with hard drive. Arcade does not come with Component Cables so you are forced to play without HD.
2.) Yes it comes with Component Cables, you can play with 720p which btw looks way better than a standard TV.
3.) The chances of you getting the 65mn are very very high. I would say the chances of you getting the older one is almost impossible since christmas has past and the 65mn started shipping in September. Even if by some slim chance you did get the older one, yes there is the 3 year warranty. I have the old one that I bought back in August, still works perfect, no problems ever.