Possibly I misunderstood, but changing the problematic plugin (the compatibility patch file) to an ESM didn't work out because it still it had errors when loading into xEdit with required masters in the wrong order, including the parent of the patch. Part of the problem is that two of the "masters" to the patch file are ESP files. Again the crux seems to be that xEdit is still obeying the plugin's master file sequence instead of the sorted one. The load errors disable any editing function.
Appreciate the suggestion though. In the meantime I'll see if changing all the PN plugins into ESMs along with both the UPP files will enable getting everything manually sorted in order to load. But none of that is going to matter if the patch plugin is still ruling the load order into the wrong sequence for my purposes.