This is pretty cool! Since a reference card with a given character's moves is included with that character, this should be easy to do in a real game -- though Vendetta (and maybe others?) has an error on his reference card, so you might need to use this site to be certain. Still, I can't see that being a real issue, since worse-case scenario you should be able to show them the card you're using it as from your discard pile or deck (if you have to use one from your deck as a reference, shuffle it back into your deck afterward). Still, with a bit of rewording, this could definitely be an Arena card!
This... not so much. I'd rather not have something like this, partly because it slows the game down because you have to ask each other about Jokers every turn to make sure you don't accidentally reveal too soon. Ironically, it's the same reasoning for why Pandante 2nd Edition removed the color requirement from the abilities: What it adds to the game isn't worth how long it takes to play with it, let alone the confusion some players will inevitably have.
Of course, anyone who wants to explore this idea can check out G. Panda! As you can see here, his innate is similar to this (which means this also falls under guideline #4 in the first post -- even if G. Panda isn't a "real" character, it's still a Yomi character being sold by Sirlin Games).
This seems like it might also cause confusion, since you have to ignore what your character card says and use another innate from a character you might not even own... It also makes some characters, like Setsuki and Onimaru, just stop functioning in significant ways (Setsuki's whole design is built around Speed of the Fox, and having strong Can't Combo normals doesn't help an Onimaru without Guard Crush).
Edit: Can't believe I didn't realize this immediately: Long Range being on anyone other than Bal-Bas-Beta (or BBB not having Long Range) pretty much breaks the game outright.