The toy bar can be removed and/or re-positioned at a 90 degree angle (flat on the ground) which is great for tummy-time. The exact location of the mount that the toy bar fits into remains fixed so you can't necessary "move" the bar closer or further out from the piano keys.
Yes, but not in the way you may think. The yellow circular domes are attached to the playmat. Only the bar comes off, and then straightens out. The yellow domes allow you to attach the play bar at a different angel, which is then suitable for tummy time. I hope this answers your question.
Yes it is, everything is moveable but the only one thing I didn't like about it that the piano is hard to detach from the two fixation legs and the first time I detached it i was afraid of breaking the toy, and it was the last time I detached it.