Well CSSU-Thumb will work with Kernel-Power as long as you use KP later than version 51r1. This has the required thumb erreta workaround.

Each of the things you have mentioned have there own wiki page.
So it's a good idea to have a look through each page before installing them. AFAIK most of the issues you found are covered in there own wiki somewhere.

I would disable extras-testing and extras-devel, then only enable extras-devel to download "foo" package and disable it after. This will speed HAM up during updates and stop it pushing unwanted update notices.

Also it's best to leave Nokia SSU enabled however you can remove Ovi if you like.

Lastly without ogg-support, you wont get ogg
If you are really worried about reinstalling it, do a full backup using the default backup and backupmenu to a uSD; then install.