there is a stomach script erf attached to the CC content that original was posted with. but you can do one yourself. Mine allows a player to be swallowed and player can attack stomach (I used invisible placeables) or the heart itself to free ooneself if enough damage is done. could be modifiend many ways and left that open to builders.
as for the ribs? Hmmm...your call, I would never say there wouldnt be a use for rib bones..lol, there is always a use for anyting these days. (:
and no...my heart was ugly to begin with, too many polys which is why I set it to juse be a simple one tile terrain. yours looks great though ! and the size differences are an awesome bonus!