From SRM perspective, do not matter if the PSC is embedded or not, the requirement to avoid a single point of failure is that each vCenter should have your own PSC. About to have external or embedded PSC with multiple vCenter, if you plan to use Enhanced Linked Mode, both PSC should be external.
For additional information about SRM and vCenter deployment models, see: Site Recovery Manager and vCenter Server Deployment Models
Should SRM server installation equal to the number of Vcenter Server located on the same site (protected site) as all 2 Vcenter server has PSC embedded??
what's will be the configuration on recovery site (Vcenter and SRM server number)???