I would be pretty shocked if they are graft compatible with anything beyond Annonaceae, but there’s no harm in trying I guess! Assuming this chart is accurate (I expect @Richard may know better than anyone else if that’s the case), I’d say start with the closer families of magnolias at least:
Edit: strike that, looks like all the other families in that order are only found in various small areas of the South Pacific, so you’re stuck with Magnoliaceae probably.