you may also need to make changes in the campaign script file which is the one which actually generates the mongol armies. If that file has references to the events file it may also have triggers based on dates which you may need to adjust.

I'm not that familiar with the vanilla M2TW campaign script but I did have to tinker with the one for Stainless Steel when I was trying to create a hotseat game where the Mongols were human-controlled