1. The length of the visa depends on the country issuing. I'm not familiar with Hungary's typical behavior for Russians here, but there are likely Russian-language resources on it, you can use translator if you're curious. We waited for the IL, but it depends on your spouse's EU travel history if it's worth starting or waiting. That's a big topic to unpack. You may have to reschedule your interview; your worry is valid.
2. As for your question, if I would've had the option to transfer to Bangkok, I would've done this in a heartbeat. They weren't accepting transfers during my time.
Good luck.