Not sure if anyone officially has in the past or for 3.5/5e but it might just be a matter of substituting PF monsters for their D&D counterpart; the tricky issue would be if there's a wholly original monster that was made for the adventure- in which case, mebbe putting in comparable PF monsters (1e, 2e, or 3pp) might be the solution? That or just creating something whole-cloth outta the relevant monster type and abilities?