Some modifications without start from nothing

ad 1) yes (although I guess you want to remove the staff with the bass clef, not only the bass clef itself): Menu -> Insert -> Instruments -> select the staff with bass clef and hit the remove button.
ad 2) no, sort of removing and reentering entering all verses

You have three lyric verses. You wish to add a first verse before the current first verse.
Try this:
1. Enter the new verse as a 4th verse.
2. Select *all* the lyrics (right click a lyric - Select - All Similar Elements) then drag them *all* down to create enough white space for the new #1 lyric (which is presently the #4 lyric).
3. Select all #4 lyrics and drag them into the white space you have recently created so that the #4 lyrics will occupy the white space formerly occupied by the #1 lyrics.

See:
http://musescore.org/en/node/25710#comment-100787

Regards.