TL;DR: Guidance for titles and usage.
Names: Hrodir (/HRO-dihr/) and Yehudah (/yeh-HOO-dah/)
As heirs: Hrodir Fyrste (/FIERCE-teh/) and Yehudah Tarkhan (/tahr-KHAHN/)
Tarkhan is a Khazar title; Fyrste is Norse.
Avoid: “princes”, feminine titles even as a joke, possessive phrasing.
In other languages: try to find distinctive titles that reflect the spirit of the Khazar titles (see below); otherwise, transliterate the Khazar titles.
Linguistic details for heralds, scribes, and others who like words
We will use the names Hrodir Fyrste and Yehudah Tarkhan.
«Fyrste», like «prince», derives from the Latin concept of “first head”, «princeps». Old Norse translated the word; modern English borrowed the cognate «prince» from French via the Normans.
«Tarkhan» was actually a military title in Khazaria, but is one of the few documentable titles below reigning royalty but above territorial governor. There is a Turkic title, «Tegin», that we considered as plausibly Khazar and actually translates as «prince», but there’s no firm documentation Khazaria used it. Thus, even though Yehudah is not remotely martial in his activity, we decided to err on the side of documentable for the place and time.
As heirs, the singular «prince» is fine in a pinch for either, but we wish to avoid the plural «princes» since this is too easily confused with «princess».
For heralds, a possible boast when we are heirs might be:
“…for their Serene and Stellar Highnesses, Hrodir Fyrste and Yehudah Tarkhan, Heirs to the Gryphon Thrones…”
And for the “long-lives”
“Long Live the Heirs”
[In practice, “Long Live the Fyrste and Tarkhan” was used.]