Also, an infinite I discovered (works on everyone except for Goomba obviously)! CH or DR -> SD -> AM (technically optional since it's not really required) -> ACH -> SD -> AH -> SD -> DR. It's pretty precise, especially for Sonic, but pretty easy to pull off.
Edit: Turns out you need to ACH twice for Sonic, still works for the Bros tho. So for Sonic, it would be CH or DR -> SD -> AM (optional) -> ACH -> SD -> AM (optional) -> ACH -> SD-> AH -> SD -> DR. Still not too complicated