Much of the work was done with the help of https://rapideditor.org/, although there was also a LOT of manual tracing and corrections along the way.
We have so much new development in the area that I had to rely on some pretty updated satellite images and local surveying to get most of that done (with more to be done in the future as several hundred more homes go up this year).
I used a combination of Bing, ESRI world imagery (the regular, not "clarity" beta), and Maxxar Premium imagery.
The traced buildings go to OSM.
Meta uses OSM, but lots of other entities do, too.
So, if I’m correct then Meta has no ‚rights‘ on your work, but uses it, as part of OSM.