59.94 to 29.97

On a terranex, any reason why I couldn't half the scan rate (for streaming)? No embedded audio.

It will work. You may not like the visual result of the conversion, but it depends on your source. If there's not a lot of motion, it should be fine.

It will be fine. In worse can it may do bit of "strobing".
Conversion is as simple as skipping every 2nd frame.
You can do it very easily on file level as well.