I installed an ancient SailfishOS image on the tablet, which was mostly broken; but it was the only version I could find for the Nexus 7. (The Plasma Active 4 image was even older, but at least it worked.) With the SDK, I can create an up-to-date armv7hl image (which, crossing my fingers, will be compatible with the Nexus 7 -- I'm still trying to work out whether I need to configure Hybris manually), but presumably lacking a UI; so, I next need to figure out how to add a minimal UI to the thing. So yes, my understanding is that Lipstick exists in the minimal Mer build, and I just need to add a Lipstick-Home package. I think.

Anyway, yeah, I'm kinda just starting from scratch, and learning how everything works.