This is almost, but not quite, an okay solution for me. I’ve hit a bug:
if your Actor has a Call-In-Editor function (MyFunction) which spawns a Child Actor using a Child Actor Component, that Child Actor’s ConstructionScript will run ***only ***if MyFunction was not called from an Editor Utility Widget. That is, clicking the MyFunction button in the Actor’s details panel works fine, but if you call that same function on the selected actor from an Editor Utility Widget, the newly-created child actor’s ConstructionScript will not run.
EDIT: This also happens for non-Child Actors. Any Actor created by the Actor having the function called on it won’t run its ConstructionScript if the function was called from an EditorUtilityWidget. I was able to work around this by giving every actor a Generate function instead of ConstructionScript, and calling that through an interface. Seems alright!