I have not tried modding Witcher 3 at all yet, & I only just recently started playing it, but I think if there is a simple way to replace the hissing & growling sound files so they are copies of the other happy meowing files that would be a quick fix that is reasonable. Having the cats rub up against Geralt's legs would probably take a lot higher level of modding to do, unless the cats already have these animations & use them on other NPCs. Like I said, I only just started playing the game so I don't know the answer to that. I did read somewhere that in the books cat's don't like witchers, & that's most likely why this was put in the game. I also read somewhere that this was added in by a patch, so maybe there is a way to disable that part of the patch? I found this thread because I too am interested in a mod that makes cat's be more friendly. I only just downloaded the mod kit today & still haven't figured out how to use it. If this is something that would be easy to do for more skilled modders then consider this a mod request, but otherwise I may try to figure out how to replace the hissing & growling sound effect files with existing meowing sound files, as that seems to be the easiest solution that should require the least amount of modding skills.