Yes, you can SSH into the device and change a config file. This is a hacker's dream indeed.

How fast is the data transfer?

Do you think one could hack it into a "screen" by streaming a black-and-white image data from a computer to it?

So the connected computer would do all the heavy lifting related to rendering, compress the result to something that is really easy to decompress, send it over, and tablet would just decompress a bitmap and blit it to the screen?

Haven't tried, but you're either limited by USB2.0 or the wifi chip.

Given the low refresh rate of the panel, something like that should work just fine. Pretty sure I saw a YouTube video by someone who hacked it together using periodic screenshots.