There was an interview with Billy Root published in Cadence where he stated that the "last concert" actually occurred over a year earlier - May 31, 1955. The later date made for a better story but wasn't true.
Don't know if Sarah Vaughan's Musicraft recording of "If You Could See Me Now" (w. Freddy Webster)has been mentioned. I'm not a big Sarah Vaughan fan, but I like that one.