I would imagine that a couple could be put in public buildings (Like I said, there is an organ in Emain Church).
And buying them for your house sounds like a good idea. :D
It would be so crowded though they would probably have to put you in like a single player mode where only you can hear the piano or organ playing
BTW Installing wouldn't be a good idea since: 1. Pianos take forever to "install" 2. It doesn't look right "installing a piano" why? I don't because your installing a giant mass space into dunbarton etc 3. Pianos everywhere would block places like making a wall of pianos with a group of friends to block people from getting in/out of dunbarton