If your taking the car down to bare metal, I would apply 2 coats of Epoxy primer. I have recently tried SPI and I'm very happy with the results. It's applies and lays down well, good sanding qualities and gives great adhesion. As far as quantity...I don't know...are you painting inside the engine compartment, door jams, under the hood, inside the trunk...underneath of the body?
As far as brand goes...they all work...the easiest for you would be to visit your nearest Dupont Dealer and ask to see color chips called "Hot Hues"...they are basically a solid base coat with a pearl mid coat and they have numerous "pearls over Yellow" color chips. As far as how much? Again, how much of the car are you painting?
Your mid coat and how much pearl...if you go the Dupont Hot Hues way, they have formulas that will tell you exactly how much pearl for a specific color...you choose the color from a chip and they can mix the paint for you. As far as over lap goes...have you ever painted before or are you having somebody else paint it for you? If your painting the car and, no offence but by the questions your asking it doesn't sound like you have all that much experience, a "tri-coat" paint job is fairly ambitious for someone that isn't well versed in painting...a whole bunch can go wrong.
So if you can answer a few of these questions I hope I can give you better information.