I made a graph that allows you to edit any family type parameter, for any built in category, in all your immediately linked revit files. You can either specify the specific family type to edit, or push the edit to all family types of a given family across all your immediately linked files. The graph requires no packages, just a bit of python magic and the standard dynamo nodes. Example below, download link underneath. Let me know if you get it working, or if you have any problems. Make sure to read the READ ME note.
EditTypParamInLnk.dyn (24.2 KB)
Technical Designer - JZMK Partners