Again, i'm not that good with shaders yet And it seems like I misunderstood some of your questions..
First of all: YES, it is fixed by removing the col.rgb *= col.a;
The shader is correct, but the _Alpha variable is used for some other special effects that I didn't include in my shipit, so it was a bit redundant.
As for the overrides, I have 2 materials: one that Spine made for me with the Spine shader (mat.shader) and another different material with my own shader (WaveController.Instance.enemyShader)
Thank you so much for your time, help and extra information! I really appreciate it!