I think that you could create your character in other way. For example you could create or use (there is a nice plugin for this purpose in the scirra forums) a plugin to create objects from a family it some degree of dynamism.
Lets suppose this:
- ryu and ken belong to fighter family
- player 1 chooses ryu and player 2 chooses ken
- then you store the names of the charaters (ryu and ken) in some dictionary where the player 1 is key 1 and player 2 key 2 and the names stored are those of the characters
- then you take both keys and its respective values and use (sorry I cant paste url but look for [Plugin] Nickname, [Behavior] Nickname in google with Construct 2 appended and you should find it) plugin to create your desired sprite accordingly, note that you will still have all the functionality for both sprites as defined in your family
Hope it helps not quite sure since I might have not understood your purpose.