vSAN and VMware NSX-T can be deployed and coexist in the same vSphere infrastructure.
NSX-T does not support the configuration of the vSAN data network over an NSX-managed VXLAN or Geneve overlay.
vSAN and NSX-T are compatible. vSAN and NSX-T are not dependent on each other to deliver their functionalities, resources, and services.
However, you cannot place the vSAN network traffic on an NSX-managed VxLAN/Geneve overlay. NSX-T does not support the configuration of the vSAN data network traffic over an NSX-managed VxLAN/Geneve overlay.
One reason VMkernel traffic is not supported over the NSX-managed VxLAN overlay is to avoid any circular dependency between the VMkernel networks and the VxLAN overlay that they support. The logical networks delivered with the NSX-managed VxLAN overlay are used by virtual machines, which require network mobility and flexibility.
When you implement LACP/LAG in NSX-T, the biggest issue with LAG is when it is used in a Cisco Nexus environment that defines the LAGs as virtual port channels (vPCs). Having a VPC implies you cannot run any dynamic routing protocol from edge devices to the physical Cisco switches, because Cisco does not support this.