The sunroof is EASY, and it is done ALL the time. Dealers farm the job out to custom shops, many of which just do power sunroofs, and the final results are a power slider that looks factory and sometimes is even better--with things like auto close, rain sensors, etc.
Here's one of many brands used, with good pictures:
http://www.webasto.us/am/en/am_auto_sunroofs.html
http://www.webastoshowroom.com/index02.html
Another common brand is ASC. You can find installers all over, and generally the price installed is the same or not much more than a factory sunroof option.
As for the power liftgate...that's a big NO. It's more than just the mechanism, including different wiring harnesses, body computer programming, etc. This is one thing that can't be added, at least using factory parts, without a great amount of work and expense.