Cob: plumbing? composting toilets?

[loving mama]

I've been lurking a bit, read the discussion about whether to leave conduit
exposed or embed it in the cob, also read a bit of discussion about pipes
used for heating imbedded in floors.

I'm curious as to whether people run pipes through the cob, and if so, what
if one needs repair?  In my "conventional" home, most plumbing is more or
less exposed (cosmetically masked by fixtures and cupboards, et cetera), and
then goes through the floor to be exposed again in the basement.  Is the
same system used in most cob homes?  What are YOU doing about plumbing?

Also, has anyone here had experience with composting toilets?  What are the
pros and cons?

Thanks!