To support two host failures with vSAN Erasure Coding, specifically using RAID-6 (4+2) Erasure Coding, a minimum of 6 hosts is required. RAID-6 allows data to tolerate two simultaneous failures by distributing parity data across the hosts, which provides fault tolerance with a lower storage overhead compared to mirroring.
3 hosts or 4 hosts would not support RAID-6 and would be limited to RAID-1 (mirroring) configurations. 5 hosts are also inadequate because RAID-6 requires at least 6 hosts to achieve the 4+2 configuration.

For deploying Workload Management (vSphere with Tanzu) to a new workload domain in VMware Cloud Foundation (VCF) using SDDC Manager, an NSX Manager cluster specifically configured for Workload Management is required in the Workload Domain. This NSX Manager provides the necessary network capabilities for Tanzu Kubernetes Grid and integrates with the workload domain's vSphere environment, enabling Kubernetes orchestration and networking.