I eventually understood how worked the aiNameOffset, and thus know how to display new leaders names for a new civilization!
The number that appears next to aiNameOffset is a gap between the last string of Age of Kings names & the first string of Conquerors names OR, as Forgotten Empires did, another string. Just remember that the last AOK string isn't the one containing Ethelred the Unready (the last name displayed for AOK civs), but the last you COULD write. So, although Ethelred is displayed at string 4656, it is however from 4660 that you must calculate the gap, since it's the maximum possible (id est, you can add 4 names max. for the Celts if you wish to).
So by default, the gap is between 4660 and 4800, the string displaying the number of names used by the Spanish civ. 4800-4660 = 140, the default number for aiNameOffset. Problem is, there is few space left after the Koreans, the last civ displayed. So if you wish to add new names for your new civs, you have two solutions:
-adding a new resource folder after the one containing the Korean names, so that you may continue the initial list of strings
OR
-moving all the Conquerors civilizations names to another resource folder (so other strings) in order to get more spaces for your new civs.
I'd advise the 2nd one (that FE used) because it's true you won't have enough space to add new names after the Korean ones, and also because Pebble and Resource Hacker don't seem to be able to add completely new resource folders (at least, me I didn't manage to).
Thanks to the FE team for that, not because I asked them, but because I checked their .dll and finally understood how they did: bravo!
I think it's worth adding that in the main post, so hopefully LmScar is back soon...
"Vous vous rendez compte, la France est le seul pays au monde où l'on recycle toujours les mêmes hommes politiques, même lorsqu'ils ont échoué !" Nicolas Dupont-Aignan
AGE OF VOIVODS
Still looking for DANISH, UKRAINIAN, LITHUANIAN and HUNGARIAN voices.