Wow, ok, where to begin?
3 & 4) I think you're looking in the right direction with the HTChomeplug, but I've not seen a difinitive guide to configuring it. I believe there are a couple of xml files but I've not been able to find it.
5) I'm not sure about this off the top of my head but if you like the phone pad layout then you can try this one, I prefer it:
Keyboard applications for Windows Mobile — Online Diary
6) Schaps configuration tool will do this for you. Get it here:
http://www.4winmobile.com/forums/sch...02-2008-a.html
7) Soft key changer is here:
Links and Downloads Manager - 4WinMobile.com
A lot of the stuff you're looking at changing can be done with SpB Mobile Shell, and although not free is an excellent program. Have you looked at that?