Before flying to Virginia retain a lawyer in Virginia so that he/she can arrange for your husband to turn himself in. Otherwise, he may be arrested and have to spend time in jail waiting to bond out.
Regarding bond: There should be a bond amount on the warrant. The attorney can find out what that is. Your husband can either use a bondsman (if so line one up in advance -- the VA attorney should be able to help you with that too), or you can post a cash bond for the amount. The advantage of the cash bond is that you save the bondsman's fee (usually 10-15% of the bond amount). The downside is you tie up that money until the case is disposed of.
A motion to quash would not be successful at this point since there has been no evidence presented. If it goes to trial
, it will simply be a factual issue for the finder for fact (either a jury or judge) to decide who is telling the truth and who is not.
It's possible that once you hire an attorney in VA, he/she may be able to talk to the prosecutor before you even fly out there and give you a better assessment of the situation, what the police reports
say, and what the photograph of her finger looks like.
My guess is that they will offer him some form of probation (most likely something that can later be expunged from his record), fines, and cost. Whether your husband wants to take that or not since he did not do what they allege will be up to him.
It is possible, although probably not likely, that your attorney could convince the prosecutor to dismiss the charge. No way to know until he/she talks to them.
Best of luck to you and your husband.