On a DTV it's fine. Interviewing someone for a video is well within the bounds of content creation activities allowed on a DTV. It irks me when people say you can't work in Thailand on a DTV. You absolutely CAN work in Thailand on a DTV, you just can't work for a Thai company. The DTV was literally designed for digital nomads to come and work (for themselves or a foreign employer) in Thailand.

Try just using the details of the flight you would take if you were approved. If they ask for proof of purchase as a follow up, buy the ticket then. From what I've read, not all embassies ask for proof that you've actually bought a ticket.

Hold up. Do some people actually attend the courses they've used to get their DTVs?

And yet there is a section for departure information, hence my question.