Questions: please when you add questions try number lists it’s easy to answer. 
1 - Walls are in groups, it’s done like that because is easy to integrate other sprites to act as walls, the variables created just to ensure the collision. I couldn’t find a better way to do this, note I’m total noob in GDevelop.
2 - 1 event sheet or 20 event sheets, is the same if the code works, it’s ok no?
3 - Some of the animations, triggers again when try to limit the attack number.
When I have some time i will remake the state machine to just one variable, right now I’m with A Pixel Adventure Legion and is a lot of work to do there.