Johnny Ray came up at least, in the episode where Jack said he was going to pay Dennis by writing him in for president.  Dennis says "If I'm elected, I'm going to declare war on Johnny Ray!" and then briefly sings a mocking first first verse of "Cry".

I like Rochester eating Jack's omelette! 😎

That opening Lucky Strike dancing logo commercial was pretty high quality considering the technology back then.
It is also great when Eddie Anderson lets us see some of his other talents. He was a very multitalented performer.

I wish that, at least for the television programs, that Eddie "Rochester" Anderson would have had a number of opportunities to showcase both his dancing and singing abilities.  I saw two Jack Benny episodes where he sang in one and danced and sang in another.  I enjoyed watching him, for he was quite talented in those areas.  I've heard a couple of stories regarding Mr. Anderson with respect to how he came by that "raspy" voice, but I don't believe there is still anything definitive about its origin at this point (although I haven't researched it on the internet).  One story I heard/read was, that because he sold the daily edition of a newspaper on a given street corner, and the traditional yelling out of "Extra! Extra! Read all about it!"  or whatever other "song/chant bit" he used to lure customers into buying the newspaper, this caused his vocal cords to become permanently damaged.  ( But I would love to have somebody write in the "Comments" section what they think is the true story behind his most unusual, but quite wonderful and charming, voice. )

HIIIIIIYAAAA, Buck!  Recently, you said that you were disappointed that you couldn't hear Kenny Baker sing "Blueberry Hill."  Well, I can't help with that, but I can help with the next best thing, Dennis singing "Blueberry Hill."  It's in the November 10, 1940 episode and I just heard it on OTR Gold.  In fact, you don't even have to listen to the whole show, though I would recommend it.

Blueberry Hill (1940) - Dennis Day
https://www.youtube.com/watch?v=6P08coDbx8E