Like I already said:
If these were 2.2 ROMS there is a known issue with the mute button.
From what I understand when in call, if you tilt a certain way it activates the mute button. The mute button IS NOT A HARDWARE issue.
Some people have also noted problems with music players, but I think that is a smaller issue and can be solved with using a different music app.
It doesn't matter what 2.2 ROM you go to, the mute issue will remain present, I believe some developers are working on a fix, but I am not 100% sure about that.
If you completely unroot and go back stock, no, verizon cannot tell you were rooted as long as you remove all traces of it.