Can we only migrate to certain states or will these states change?

There can be some restrictions depending on your current province and possibly for seasonal events. State 80 is open now but may be outside of your current bracket. If you go to the Province immigration event and check for Province 80 you will see if it is available now. If its not currently available to you then the range of provinces that you can move to will apparently expand over time, but I don't know when this may be. The in game support may be able to advise you further.