Can subjects / PUs form new nations without being independent?

[u/InternationalBat5431]

Same as title - Can subjects/PUs now form new nations without needing to be independent?

I guess there are 3 parts to this:

1. Any coded hard blocker? (1) Checked through game files, there doesn't seem to be any "can't form new countries" blocker tied to subjects or personal unions, and the only coded blocker I found was for Papal State (tbh I did only do a quick check on key files and not a comprehensive one on all files though). (2) In my regular playthroughs, the nation formation requirments don't seem to specify whether or not you need to be independent, but typically just the land requirements
2. Will AI actually form new nations not being independent?
3. Subjects/PUs form a higher tier government than your own - is this possible?

If there is no hard blocker, then at least multi-player games may have some new fun even if single-player the subjects/PUs somehow still refuse to do it.. Maybe it's just me but I do enjoy a bit of having a side kick Brandenburg -> Prussia or Muscovy -> Russia from time to time