2. E-file for Form 3115 is unsupported but e-file for Form 4797 is supported.
See https://care-cdn.prodsupportsite.a.intuit.com/forms-availability/turbotax_fed_online_individual.html
Form 8453 has a checkbox for Form 3115 so you should be able to e-file your return and then print and mail Form 8453 with Form 3115.
