I do not have vampires, but, don't think it makes any difference what the sim life state is.
Whatever time, day or night, that you type resetsim", all the sims in the town are returned to their home. As your sims will return home, I wouldn't think being a vampire would be a problem.
Remember, that the sims in the community facilities, such as the consignment store will also be reset. So, you will not be able to use these facilities immediately. The staff should return quite quickly though.
If this does not work, then do as Pam says and evict them. When returned to their home there is a very good chance that the problem will be resolved.