I modified SSCSEditor with some new functionality and it all seems to be working great so far. However, the 3D component preview doesn’t update until I either reopen the blueprint, or modify a property in the components like a position. Then suddenly all of the new component nodes I had added show up.
I tried to look at how the code for things like Pasting nodes was done in case I missed something, but as far as I know, calling FBlueprintEditorUtils::MarkBlueprintAsStructurallyModified(Blueprint); is the only thing I see done in functions that cause updates.