Supposing there is an arrest warrant against a person in Virginia for a felony he has committed recently. Right now he is residing in another state. Will this warrant ever expunge?

An arrest warrant in Virginia (as well as in any other state in the USA) does not disappear out of itself. If it is not served, it becomes an outstanding warrant. An outstanding warrant can still be used to arrest a person. The only way to make an arrest warrant expunge is to hire a good lawyer and address the problem in court.