Interesting answers here are from Plamen, from Braxtech:
Q: Will there be an easily buildable close-to-mainline Linux kernel?
Will changes be upstreamed to the mainline linux kernel?
A: Yes, to both. We’re getting that promise from MediaTek and the integrator they hired for the linux part.
Q: Will fingerprint support work on linux? How will the camera look? Should we expect the camera to be green and blurry at the start?
A: The mandate is to get everything working, as it will on Android. We will communicate a linux roadmap in due course. One of the main reasons for selecting the g720 by MediaTek (and not a way cheaper alternative such as Rockchip 3588) was the strategic importance for MediaTek to run linux on it - this is their latest high end IoT chip. Most of their customers for the chip will run Linux.
Obviously, the camera won’t beat iPad, but it will not be crap.