Plot's always good. Depends on whether you want it to be a 'zombie's exist and everyone knows about them' or a 'starts out as some bizarre infection that turns into an epidemic' thing.

If it's a common knowledge thing, I would think Steve, being a SEAL, would've dealt with them before so would be totally cool with taking over defense of the islands. Danny, on the other hand, would have many, many issues with the whole zombie thing. His ranting would be epic and a thing of beauty. :D