SRM 5.1.1 in Production

Dear All, I am implementing SRM 5.1.1 into production and I have some doubts/ questions in my mind. I would really appreciate if somebody can clarify these for me... Please?

Site A (Protected):

1. vCenter 5.1 VM
2. SSO VM
3. vCenter DB & SRM DB VM
4. SRM VM

Site B (Recovery):

1. vCenter 5.1 VM
2. SRM VM

Questions:

1. Should I create another DB and SSO server for vCenter at site B? Or it can use the ones at site A? If it uses SIte A DB and SSO, will SRM work when we do planned DR or during disaster?
2. Should vCenter be in linked mode or Separate at each site?
3. If we have 3^rd Site (Say Site C) which is also a recovery site. Can we configure SRM in such a way that Site A VMs (Protected Site VMs) and failover to both Recovery Sites? ALso Do I need 3rd vCenter, SSO, DB at 3rd Site?

Many Thanks,

AG