So here I want to request two different scripts (with the first one being more important to me).
The first one would add champion enemies (as the name suggests). If you have ever played The Binding of Isaac, you should know what I mean

If you don't know that game, continue reading...
By "champion" enemies I mean that, usually on random encounters, some of the enemies in a troop (picked at random) will become more powerful. This would range from only certain stat increases, to new traits and skills. And I don't want it to be totally random, but to have a player-configured set of champion types. So for example we could have 4 champion types:
-Red, that has 200% of a non-champion enemy's HP
-Yellow, that has 200% of non-champion enemy's AGI
-Grey, that has 200% of non-champion enemy's ATK and MAT but only 50% of their HP
-Green, that is immune to poison damage and Poison state and has a new skill called Toxic Bite.
The second script request is less important for me but also less complicated... I just want some of skills to completely disable the "Null" popup (I'm using Yanfly's Battle Engine). To be more specific, I have some skills that inflict a state to the user. To do that, I need to set the damage formula to sth like this:
a.add_state(10); 0
The skill will work as intented and will inflict the requested state but it'll also create a popup informing that no damage was dealt AKA the "Null" popup.