Here is a collection of potentially useful sources that I either have used or want to use, and in any case want to save for future reference. Please feel free to make use of them yourself! I hope that these can be of use to someone in expanding the wiki:
[1]: Contains several PDFs of various Ancient Rome-related topics. The site is in Hungarian but the files are in English.
Géographie économique et administrative de l'Égypte: Detailed census (?) data of several parts of Lower Egypt (Qalyubia, Dakahlia, Sharqia, and Damietta) in 1902. I don't think it's technically a census but it's got that sort of info.
Recensement général de l'Égypte: An official but less detailed Egyptian census from 1885; only lists population of settlements but it covers the entire country.
Matériaux pour servir à la géographie de l'Égypte: Very old French work listing various locations in medieval Egypt. Often not especially detailed but there's a lot here that isn't on Wikipedia yet.