I don't want to come across as a know-it-all nor as someone that is insulting you -- I just want to help you understand the code behind this release.
Just to get this out of the way; you may be overcomplicating (knowingly or not) the method the PS Vita uses to retain your PSN info.
The PS Vita retains your activation info via its registry as well as a data file that lives on your memory card (this is how the card is linked to your account).
This is the code behind this release:https://github.com/SilicaAndPina/Simple ... src/main.c
All this does:
- clears login and password from registry
- removes data file (with account info) from memory card (therefore allowing it to be used with another account)
- starts the psn sign up app (allowing you to log-in or create an account)
As for your questions:
1: Your PSN info (on your PS Vita) is saved on your system (as described above) -- PSN (the service) keeps a record (your PS Vita ID) when you activate it, but it does not need to be removed from PSN for the same PS Vita to work on another region (maybe for another account in the same region, but this needs to be confirmed).
As for deactivation, only the built-in app can deactivate your PSN account from the PS Vita (as well as the entry on PSN), but then you will need to set up your PS Vita once again as per usual.
2: Nothing -- you won't be able to switch your account easily, nothing complicated here. Only side effect here is that you'll have to do it the hard way.
3: Yes -- you'll be on whatever account you switched to (same as when do a reset with the PS Vita and log-in to another account).
You may be overthinking this one -- but basically, think of this utility app as a fast forward button to help you go from a region to another (without having you clear your memory card, and without having to watch a video when setting up the system).
I hope I was able to clarify this for you a bit more - - let me know if I can make anything easier to understand.