To create your own cheats, you can use Dolphin's cheat support to try and search for values to modify the game. Some of what you listed sounds easy (cheat to go in the sunlight...) some of it sounds like it'd be hard (playing as characters that didn't exist in the original game.)
My best bet would be to just start poking around the game with the built in cheat stuff. It's in Tools/Cheat manager I think or something along those lines.
My best bet would be to just start poking around the game with the built in cheat stuff. It's in Tools/Cheat manager I think or something along those lines.