LaTeX's figures, tables, and \marginpar's are dangerous for footnotes (and probably \enlargethispage). Here is a proposal (a "patch" .sty) to help using \holdinginserts in a simple way. It replaces the original problem with a new one -- it is an experiment to find out whether the new problem is less bad (or it is just a contribution to the discussion, maybe just a summary of previous work). The files provide further information.