Hi Keegan, I have heard of these kinds of problems reported by several people in T. marmoratus - spine or tail bent, eventually stop eating. The bulges in the abdomen that you describe sound different though.
I had 2 marmoratus that were perfectly healthy, then both developed a lump (later confirmed to be a spinal curvature), stopped eating, and eventually died. Here is a photo of one of them:
I don't know what the most likely causes would be. But if you've had two of them with similar symptoms, I think MBD is a possibility. My marmoratus in the photo was fed mostly earthworms, which are supposed to be a good source of calcium, so I don't know what the deal is.