Hello Davide, This is a good initiative.
I haven't updated the screenshots yet; I wanted to wait until #374902 gets fixed since it seems to affect quite a few languages. As far as coverage is concerned, I think we reached a stable situation, with georgian font being the only tarball in need to be replaced by the udeb.
The Georgian fonts in the udeb package are under GPL, so we could replace the Georgian portion of Dejavu with the one from Georgian udeb packae (BPG Glaho being the best font). Regards, Aiet