I suspect the delay in startup is because of the filesystems. If something blew out, I am guessing your filesystem needs an fsck. You might want to try and do a sync, just to put your filesystems and database file back in order.

Given the blown main fuse, I am guessing that the nipple on the display itself should be fine. I am guessing the fuses to the display board are gone, but that would not explain why the buttons don't work. Can you confirm that while playing a song?