i don’t see what’s wrong with a jewish singer using a tune from a goyish song. i used to think that was hypocritcal but now i realize that it isn’t the tune that is infused with tum’ah, it’s the lyrics and the singer.
The way I see it, if you know the original, you will be thinking about it while hearing the Jewish music. If the song is vulgar or something, it might make you think vulgar thoughts about this nice Jewish song. If you never heard the original, it wouldn’t be a problem(IMHO).
Truth be told I don’t like music. When I was a teenager, I tried listening to music so I wouldn’t be “behind the times” but never foudn anything I connected to, just non-sensical vulgar words streamed to music.