Daniel,
In that case, is there a reason the placeholder refnote cannot just become the final item? It all really depends on the workflow, and we're happy to see examples, and how it can better respond. For instance I've certainly seen plans that have multiple callouts all stacked next to each with a single leader pointing to the item. At some point in the future we definitely will tackle this in some fashion, as it is an obvious need.
Another thing is to have the placeholder refnote item still be the correct object type. As in, if it is going to eventually be an Amenity, it should be initially placed as such, and not as a notation. But along those lines, I can certainly see it being handy to be able to "upgrade" a generic notation, to now be pointing to a placed amenity or chosen layer.
--J