The most significant issue is that the HTML editor alwasy wraps <p> tags round the input, but that is not appropriate for the choices. It is especially not appropriate because we want to display the choices in a <lable> for accessibility and usability reasons. In valid HTML label can only contain inline elemnts. Therefore, I introduced a make_html_inline method, with a minimal implementation. (It could be improved in future.)
Long term, I think the best option would be a new form field type, editorinline, or something like that. That would be a smaller version of TinyMCE that only lets you enter inline elements.
Tim Hunt