So i was thinking that if there was a state creator tool you could assign provinces to become their own state and you could name them, set the population, set the factories etc. This would be extremley helpful and useful.

This will be implemented as part of a larger map creator tool, which isn't planned to be worked on for at least a few months.

However, you should be able to do most of what you are looking for with the game's nudge tool, this video should help (if you wish to use it): https://www.youtube.com/watch?v=YbViu2xl--s