Ok, I understand now.
Yes, you can still import individual players from any real year. If you want Cobb from 1910, you can have him, or 1915, whatever year.
Go to the league FA screen, import historical player. Those steps really haven't changed, even from way back in 6.5 During import you'll be given the option which year to import from. OOTP still uses the lahman id, that hasn't changed either. BB Ref is one place to get the lahman id as I'm sure you're aware.
So that should be easy for you.
You can import historical players into fictional or real or mixed, any league at you have.
As for divisions, you can change them. In league setup, there's an option to "edit league structure". Do it in there. Just remember what I said earlier about generating the new schedule after you edit the structure.
Good luck and let us know how you're making out.