Can there be a cross over to federal and state misdemeanors? So one commits a federal misdemeanor while CCwing and gets charged by the state for a felony?
Yes.
Jurisdiction matters.
For example, if you break a state law, then the state can claim jurisdiction.
If you commit the same crime but it happened on, say, a military base, that becomes federal jurisdiction. Unless you were in a federal building, on federal property, committing the crime in multiple states, are a federal employee, etc, etc, then chances are good only the state will charge you.
Some crimes like kidnapping and bank robbery are automatically federal jurisdiction.
Normally, you can't be charged with the same crime twice. The agencies would have to make a call on who's jurisdiction will take precedence.
Often the feds will claim jurisdiction if they can. If the federal law classifies your crime as a felony and the local law say it's a misdemeanor, your lawyer should be negotiating with the state to get a plea on the misdemeanor before the feds arrign you. Timing matters.
Once the feds present a charging document, they can even walk into your state trial at any time before the verdict and arrest you.