Yup....definitely Mike Lally!

I appreciate the strong interest in this topic.

The suggestion of James Gregory is interesting. If he really appeared in "It's a Mad Mad Mad Mad World," I overlooked it. He was not the actor I had in mind.

According to the Internet Movie Database, Buddy Hackett, one of the main stars of "It's a Mad Mad Mad Mad World," appeared in "Walking My Baby Back Home." After reviewing the short clips of the Grace Wheeler film from "Forgotten Lady," I am fairly sure that Buddy Hackett appeared in it for only second or two. Hopefully someone out there can verify this. It would be a lot clearer to me if I had seen "Walking My Baby Back Home" in entiretly. Unfortunately I never have.

Very clever David...Very very clever!
I looked at Forgotten Lady and there is a guy there that could definitely be Buddy Hackett. It is the last scene where Grace stands up in front of the screen while the movie is running behind her. If you look really close you see a glimpse of him playing an upright piano. Then Grace's shadow blocks him. It's quick, but it could definitely be him.