no authorship -- individual or institution -- identifiers. … freeform and also contain 8-bit chars that represent different code pages

So the only possibility would be to "view in Latin-16, ISO-8859-8, KOI8-R, Windows-1256, etc and decide which one is looking right". Urgh. Well, perhaps some reCAPTCHA-like system could work over time...

species name. Specifically, the character that combines a & e into a single char.

If it's only æ and œ, I think these are since medieval times used in latin texts.

I am able to choose what work I take on;

Lucky you. That means, if you took on this project, it wouldn't be because of the money, but because of the challenge :-)