I suggest adding the following points:
* When Sir Mullich, Izra, and Vidomina are freed from prison, they can be used without restrictions on the day of their release. Points 5.10.1 and 5.10.3 apply to them starting the next day.
* If Sir Mullich, Izra, or Vidomina are together with an enemy hero in a Portal or Underground Gate during an attack, it does not constitute a violation of the rules.
And even if he doesn't critically hit 300 skeletons that day, he can't be used afterward, so consider it like a Pandora's Box. I think it's fair gameplay.