1) Please see the FAQ link in the nav bar. there is a tutorial in there that will help you determine how big of a PSU you need.
2) People go into hibernate or stand-by all the time rather than shutting down fully. As to how to have it know when you want it to do what, not sure there's a way to do such a thing without you telling it every time.
3) TS works through USB usually. Check out the LCD forum for more info on the various screens that are avaliable.