RE: Grand Piano in a McDonald's, Indianapolis
I've never heard of live music at a McD's, but "theme" McD's have been around for some time.
The first I know of was in downtown Providence, in the mid-70s. They moved into a lovely old bank building (the early 20th century type with columns and vaulted ceilings etc.) and rather than gut the space and plasterboard it in red and yellow they maintained some of the original detail and did the interior in brass and (if I recall) green. They called it "banker's quarters."
There's a 50's inspired McD's in Framingham, Mass. that's loaded with Elvis, car culture, and rock & roll memorabilia.
If McD's did have live music in our area, it would probably be oldies. Boston's a rock & roll town, and in most of New England oldies is the "family" music.