In most caves, your feet are a pretty significant part of your contact with the environment. Whatever footwear you choose, aim for a good fit. Losing toenails on an expedition can be a problem, although less immediate than losing a too-big welly in a high flow stream passage, or while swimming.
And don’t forget to allow enough room for a decent insole! You would up a mountain, so why not in an equally rocky and uneven cave?