How about making Puerto Rico, Guam, Virgin Islands, etc all states first?
The problem (and reason why Greenland as 51st state will be thrown out) is that it would upset balance in Congress and Senate. Greenland is used on European social democracy, it is going to be blue stronghold. The islands will be likely blue as well. Republicans would be diluting their power by accepting these entities as states.
Same problem with Canada. Except Alberta, most of Canada would be voting blue as well.