It was a complex question, so I didn't mind the wait!

So appearances and color schemes are a go, but does that include skills as well? Rider incorporated lightning elemental abilities into his attacks and his chariot (when he wasn't using his game breaking Reality Marble), and Caster!Waver has a combat skill that alters the terrain. While I'm aware that they can't be directly used in their canon form, are elements from these allowed as well?