Glen Burtnik and Styx

I was watching some Styx videos and found this song “Love is the Ritual”.
It was witten and sang by Glen Buertnik when he was replacing Tommy Shaw at guitar. Later, after Tommy’s return he is re-hired by Styx, this time at bass, and he sang the same song on a different instrument while the guitar parts he wrote were platyed by Shaw.

Is there any other case of a musician being hired twice by a band and playing two different isntruments?

This isn’t quite what you’re asking, but there’s the case of Daryl Stuermer, who plays guitar and bass with Genesis when they tour. He and Mike Rutherford switch off, because Rutherford isn’t the greatest guitar player, so Stuermer plays guitar on the older stuff, that originally done by Steve Hackett.