Wait, so K-KA and 66th members are allowed to join regiments which are playing in EIC, right?
I have said it multiple times, it's done on a case by case basis. For example I would allow Fwuffy and Salakien to play for 56e as they are Czech and have previous ties to their regiment, but I won't be allowing Marquez to play for 96y as he is Spanish which makes no sense.
Also this goes for everyone, don't try and change the names of people from K-KA and 66th when adding them to your roster, I will know. Hinting at you 96y.