Mounting plumbing to existing outdoor deck. What kind of pipes and fittings should I use?
You will need to adapt from PVC to hose thread if using hose thread quick disconnects. If you can find pipe thread (on the fixed side) quick disconnects that would be one less fitting to adapt, as PVC to pipethread is a standard fitting, and I'm not aware of any direct PVC to hose thread fittings (may exist, I've never seen one) so I expect you'd need a pipe thread to hose thread adapter as well as the PVC to pipe thread adapter to use a hose thread quick disconnect.
PVC outside needs to be protected from the sun - a coat of paint will do, locating it under the deck may do if sunlight does not penetrate the deck. Any exposed PVC needs to be painted or otherwise protected from sunlight, and you need to be religious about draining it before freezing weather. Other types of plastic may be more forgiving of both sun and freezing (black polyethylene, for instance.)
Not much in the way of design details provided to critique, other than items already mentioned in 1 &amp; 2.