most fighting games have Hitboxes that deal damage, hurtboxes that receive damage, and PushBoxes that keep characters from overlapping.
since your root capsule component is already a pushbox, you just need to add hurtbox and hitbox volumes to the game, and give the character an array of hitboxes and hurtboxes, updating the array during each move using anim notifies. usually, you need 3 hurtboxes (low, mid, high), and 1 hitbox, but you could make them subclasses of the same type, so the base class can handle the editor code, allowing them to be placed using the same code, and the individual classes can be used to filter the collision.
storing the data for all of these hurtboxes, for each pose, for each move, for each character, could be done with a text file or a spread sheet, but it would be hard to edit the data without a visual editor. each box could be a struct that has a bone name to attach to, and 2 vectors, for min and max coordinates defining the box. if you expose the vectors, you could get an in editor handle to adjust the sizes, and you could have a construction script that renders a color coded volume where the boxes would be spawned.
http://www.eventhubs.com/guides/2009/sep/18/guide-understanding-hit-boxes-street-fighter/
https://www.youtube.com/watch?v=ehf2NU0ktyg&index=5&list=PLAEDAFB9068FB7E58
doing all of this in blueprints would work, but to make a custom editor, or change the movement component would require c++. right now, the character movement component detects that it has landed based on the capsule touching the ground, but for some moves, that might not work so well. if your character is doing a front flip with a small capsule, you don’t want to wait until they reach the ground in order to land, you should instead be doing line traces below the capsule at the height that a standing character would have, which checks for the ground. that way, you can do a front flip over a characters head, and have your character continue the flip, even if they land on the other characters head, and they would stop flipping at the right height, without having to roll on the ground.
ideally, you would want to create something like Mugen’s Fighter Factory:
