What is the Dell EMC recommendation for VxRail Management VLANs?

A Stretched VxRail cluster is being designed with four nodes per site, for a total of eight nodes.
How many sites are required for this configuration?

Which vCenter object is created automatically when deploying VxRail with an external vCenter Server?

Dell EMC will be responsible for the configuration of ToR and Management switches for a VxRail deployment.
Where should these details be documented?

A company is in the process of configuring their Top of Rack (ToR) switches as a single rack that replicates to a secondary data center with vSphere Replication.
What is a consideration for this configuration?