Right now Plasma implements exactly zero of them in the Dashboard ScriptEngine, causing several widgets to fail when loaded.
Implementing most of these would be pretty trivial, and they can all be done one at a time. The six properties all have equivalents in the C++, so it would just be a matter of hooking those up. The eight methods are all easily implementable using the KDE libraries and several would probably be one-liners (such as the openApplication or openURL methods), the preferences flip ones would require a small amount of HTML+JS hacking to do the flip animation .. leaving just
Personally, I'm not overly motivated to work on this given everything else that's currently on my plate. It's one of those things that I will eventually get to because it needs to get done, but that's not overly inspiring, is it? ;)
It occurred to me that this would be a great little project with a very manageable scope, working on a very small body of code that is a plugin (so you don't need to reload the desktop as a whole or deal with long compiles) that would give immediate results and can be worked on one piece at a time to go from zero to fourteen.
If you are interested in working on this, please drop me an email or visit us in #plasma on irc and I'll get you started.