Registering theme in wordpress

I may have done this wrong.

I have a staging area where I am customizing the theme and it works find after registering it.

On the main site I wanted to add the one page “Coming soon” theme but my key gives me an error and the home page is blank white.

I am with wpengine so it’s not really a sub domain.

Is it possible to have both active for about a week?

If I copy everything over after I get the site the way I want it will the activation code transfer since the urls are different?

Thanks