1. Not sure why you're not seeing the blue title bar on the Comp track (imported colors from earlier version interfering, maybe?), but I think it's normal that the flattened comp will not look any different from other takes.
2. I think you can just treat the flattened comp like any other take and use Melodyne on it or Audiosnap, etc. The locking and soloing is just a convenience. You can always unsolo it, mute it, and generate a new flattened comp from the original takes to try something else.
3. Yes, you can edit the flattened comp take after unlocking it, but the Comp
track is just a representation of the active take lanes, and can't be edited directly beyond moving it.