Surprised Root Explorer won't browse ext, but haven't used sd-ext for about 10 months so memory not reliable.
The phone thinks that apps on ext are on the phone. Phone menus don't realise that ext is there at all. Everything is installed on ext unless you explicitly move it to sd.
If you just ran revolutionary you have an s-off version of the stock hboot. CM7r2 is a different hboot which partitions internal storage differently. Not a problem if it's working, but roms designed for this may be using space inefficiently, and sometimes make assumptions like "there is space to leave dalvik on internal so do that" which may not be ideal if using a stock hboot. But it sounds like you have that sorted.
If worried about bricking, boot into recovery and take a backup from there (a "nandroid" backup). That can get you out of a lot of mistakes.
And if you don't want to brick, do not use an app called ROM Manager. If it's included in that ROM, uninstall it (being S-Off means you can)