The main reason I brought it up is I had actually bought this template and the beat em up, (which also typically use hit/hurtbox) was to see how you'd set up your boxes. (I'd hoped to be able to just reuse them, if possible.)
However, your way does seem to be much simpler and easier. Especially since I'm not planning on making any kind of competitive fighting game. I don't even plan to have 2 player.
So, your system actually gave me a different, and easier, way to do what I'm hoping to, which is great.
Now, if I was planning to do something multiplayer competitive (aside from Gdevelop likely not being the best engine to use) how would you get distance to work with things like high/low attack combos? (Typically, you have at least 3 hurt boxes - head, upper, lower. Delayed jump attacks, for example, can hit the low hurtbox even if an upper block is active. )
How would a character who uses long range normals, (like Dhalsim from Street Fighter), work with range checks? Not for his own attacks, that's easy, but for getting hit? His hurtbox extends along his arm/leg when they're extended so you can either avoid or i-frame past his hitbox and counterhit.
I'm guessing you could probably do i-frames with a "cannotbehit" variable and priority could probably be handled with a "priority" variable that gets compared between two attacks, though I'm not sure how precise that would be.
Just to be clear, I'm not dissatisfied with your templates, it has a simpler method of doing something I wanted to do anyway and it very well set up and easy to follow. I like it and I've already begun making modifications (like making Mr. AI way less oppressive by increasing his random chances from 1-11 to 1-100 making him less likely to cling to you like a leech and bomb you non stop, though he's still far too aggressive, but that's fixable.) But I just tend to forward think, (probably too much) and I'm curious what your solutions to some of these issues would be, even if it's "Gdevelop just can't handle that level of complexity just yet".