Not sure Elvis heard the great opera singers. Maybe Grand Ole Opery.
Orbison, Carl Perkins, Jerry Lee Lewis and Elvis jammed one night at Sun Records. I think the CD came out awhile back and there was a broadway play, The Million Dollar Quartet.
Would liked to have been in the room.
I saw a you tube version of “Life’s Railway to Heaven” a year or so back.
Johnny Cash was doing most of the singing but the “Nitty Gritty Dirt Band”, Earl Skrugss, and the Carter Family were all singing or playing.
It was very good.