What about cases where the map doesn't change? Say it was a metadata issue, which has no effect on actual gameplay?
Regardless... if the scoreboard were removed there would no longer be any incentive to play the maps before they were ranked. People usually play maps in qualified to secure top/#1 ranks on the lower diffs (mapsets with no spinners are especially prone to this) or to get pp. I think the third option is the most ideal because people will get to keep their scores/pp if the map passes qualified.
At the same time, however, if you were to implement this, pp gain needs to be hidden from players somehow, otherwise even if a map does not immediately reward a player pp, they will still assume they have obtain those pp, and this would still create drama should a map get disqualified because players will be "expecting a top play". Basically at the end of the day, if a map is dq'ed, you are still going to get people saying "rip my 300 pp score etc etc" even if they never actually got it added onto their Top Plays (yet). I doubt this can be fully avoided, because players can always estimate about how much pp they would have received...