If I were to say that the Kaguya had any form of healing outside of their bone manipulation I would say it would require sage chakra. May that be through Curse seal, or sage mode.
Without enhancements, you have incredibly basic healing. When you pull a bone from your body, that wound would heal, and that's about it. Maybe some minor damage from Tools and what not but to keep things semi-Fair I would say no more than minor scraps and burns.
Now once you add Curse senjutsu to the mix you start getting a higher form of healing. Now you can survive pulling out your spine and producing a forest of bone (And I am pretty sure Kimmi used the bone forest without curse seal in the Kabuto fight, /but/ he may have been pooling off Kabuto or something. That whole interaction was just odd.)
Now, finally we add Sage mode chakra. I suggest this gives the healing power a run for it's money, Within reason of course. You are able to passively heal major wounds with the expenditure of large amounts of Senjutsu. I would say if you use the Kaguya healing power it would reduce your Sage mode by one turn, as to keep things fair for Healing power users.
Of course I am just throwing things out there, if you wish to ignore them, or use this as a foundation for any other rules, be my guest.