Q&A for How to Sign Up for Facebook

Yes, but do not use them for malicious or illegal purposes. If you want them be associated with each other, link them within each other's profiles and friend them.

When your birthday rolls around, Facebook will congratulate you! When other people see it, they will wish you a Happy Birthday, too!

No, but it might seem suspicious if you don't provide one. If you don't use your account for a while, it will be more likely to get automatically disabled for suspicious inactivity. You don't have to use a real photo of yourself if you don't want to. The only rules are: you can't impersonate someone and can't use inappropriate or sexual photos.

No. Any valid email address will work. A throwaway email might not work and might get treated as spam by the site.