1. Mustang dont have bridge mounting cups, only Jazzmaster and Jaguars do
2. Yes all competition models (ie Red, Blue and Orange, each one with comp stripes and USUALLY a matching headstock, unless reissue) come with pearl pickguards (but not 100% sure abou Japanese reissues)
3. Get mint green if you want, its your guitar
4. Stripes meant to be ironic? They are a racing stripe, the whole idea and paint scheme of the competition series was for it to look like a racing car. Personally, most people think they look awesome
5. There are many scale lengths, from about a handspan long to the length of your arm. Most common scales for guitars are 22.5", 24", 24.75" and 25.5". 24" and less are commonly refered to as "short scaled", 24.75" is used commonly by Gibson while 25.5" is used mostly by Fender.
6. Mustangs come in two lengths: 24" and 22.5", 24" being the most common. 22.5" is rarer, and doesnt feature on the reissues
7. Post some pictures and we probably can tell you