By the way, the .orc extension is just an extension, and not all of these files can be converted. I don't remember exactly, but one or two files definitely couldn't be converted... the developer planned to fix it, but never got around to it! However, there was a French-language website where they posted a mod with modified creature parameters... I can't name the link right now, but I'll let you know when I find it! So, it seems they managed to find a solution!
I would be extremely grateful if you could find this mod; perhaps I could understand how they did it. I'm very interested in exploring this, and maybe even trying to change the balance, because the original... well, as always in Heroes, it works on some stages of the game and on some game difficulties.
Thank you for your answer, in any case.