1. Reina and Rey: Yes, we use Q & K :)
2. Jokers: No, that super makes sense, I just don't know how well people will get it? But ROJ / NEG does seem like the best choice.
3. Visto: Yes :)
4. Todos: I mean that could work; "todos" means "all", "los dos" means "the two", and "cualquier/a" and "alguno/a" mean "any"(1). I think any of these options can work because they are all easily understandable with a guide, but my assumption was that "any" was preferable. Don't think it'll be much of a problem regardless!
Edit 1: The difference between them, as best as I can explain it, is that "cualquier/a" refers to a determinate amount of entities while "alguno/a" does not specify, and since we know the faces of a die or the sides of a coin "cualquier" makes more sense but "alguno" is likewise understandable.