4. The agreement on abstaining and letting the other bloc rule only lasted a year before KD left it and M quickly followed. It's fairly toxic with the centre-right base.
5. What will happen after the election is unclear because no one wants to answer hard questions about it. It's fairly clear M+KD would prefer ruling with SD support over having continued leftwing influence. C and L seem to not want that but it's unclear what their alternative would be.
Enough to give SD enough concessions to gain their support, or would they just be banking on their support because they wouldn't want to bring the right bloc down? If the latter, and SD don't play ball, then their unwillingness to see the left bloc govern as a minority will likely be returned.
As for the poll: V
Poll
