What is the reason for building such topology?   The usual way to implement b2b VPC is between aggregation and access switches, and agg switch in such case will be connected with several VPC pairs of access switches. Topology on the picture can be bu...

> I guess the two vPC pairs will see themselves as MST root,   Yes, there will be two separate STP domains with own roots > I should probably keep peer-switch enabled on both.   Yes, you can configure peer-switch if VPC pair is STP root.

https://www.cisco.com/c/dam/en/us/td/docs/switches/datacenter/sw/design/vpc_design/vpc_best_practices_design_guide.pdf   BPDU filtering is exact recommendation in such design: Regarding peer-switch, indeed, it should be configured on root VPC pair o...