Hi @Kevin_Anderson and Hail community.
Probably it is too late for this answer.
Anyways, if you want to go from genomics datafiles to tfrecords (that you can plug into Tensorflow or Pytorch) vía Hail, probably DNARecords is exactly what you need.
I have created a Feature Request just to check what the Hail community thinks about it.
Hoping to help!
Regards,
Andrés.