Could EPA direct the subaward directly to a Tribal nation to manage, so that our Tribe is not involved in tracking requirements that seem to be part of the post-award requirements with subawards?

The only option to pass funds to a mentoring organization is through a subaward, which does require the lead recipient (grantee) to both follow EPA’s subaward requirements and policies as outlined in the SN (see SN Sections 3D and 4C), and to provide the vehicle/mechanism for distributing the subaward to their mentoring organization.