All of them first should approve of statehood.
And no, PR hasn't. IIRC, the last referendum was terribly worded. It first asked if you like the current status, and if you voted no you could decide what status you want. Those who voted no, the majority voted for statehood.
I want to see more stars on the flag, but until the people of those lands approve of statehood, there's nothing we can do about it.
As for DC becoming a state, no. The capital should not also be a state.