I think any new breath that is breathed into FM at this point is welcome
I think SC plays the piano, bass, and lead guitars. So, she and LB could jam together, though he appears not to share the sandbox very well.
Another point is she is a star in her own right and does not need to do this and vice versa. So, it must be being done for artistic sake, which IMO will lead to a different and hopefully good sound.