Well to do the whole jeep I would say it's about 3-4 quarts. That being said, just buy a gallon of everything. You'll have some left over but you can use it for touchups/bumpers etc... It's also a lot cheaper than buying 3 individual quarts.
As for the clearcoat, it depends how flat you want to go. Hot Rod Flatz has a clearcoat that is semi-gloss, but I would label it more as semi-flat. Meaning it is a lot closer to the flat side of the spectrum rather than satin. If you want more sheen and less flat, buy a gallon of the Hot Rod Flatz, and a gallon of gloss clear, and mix the two until you reach the desired finish. Takes some experimentation.
What brands? PPG, DuPont, or BASF. However, these are all pricey, quality finishes. For a cheap Jeep re-shoot, I would use Kustom Kolor paint from TCPGobal.com. Seems to get good reviews and is dirt cheap. Maybe $200 total in paint supplies.