A1: No, it should be much faster then that. In my lab each machine takes about 30 seconds to clone and customize.
A2: Yes, that should be fine as long as you have installed and configured View Composer.
A3: Not sure if I understand your question but you should have the parent configured with DHCP and the last thing to do before shutting down and taking the snapshot you should do a ipconfig /release
// Linjo