Welcome. They aren't dumb questions but the are for the most part routine questions that could be answered with a little research. However, I admit the search engine on this site leaves a lot to be desired.
The forums here have specific topics and several of your questions should be asked in another forum. Also, you'd probably get better answers with one question per post. There are lots of knowledgeable people here that don't mind sharing their knowledge but to answer all your questions would take a bit of time. We are all hobbyists and nobody gets paid for any of this.
I'll start with question 1. Body numbers and engine numbers didn't match. Most states used engine numbers for titling purposes until the mid '50s. I believe CA was one of those states.
