As Mario, getting up from ledge against Snake is very difficult. Snake can ledge trap very easily. His up-smash covers every option except roll, so he is pretty scary. All he needs to do is plant a C4 at roll getup then wait for your invincibility run out to u-smash. So if your at ledge, your in a bad situation. The best option for Mario honestly to choose an option quickly, before Snake can set up his traps. Unless he sets them up before you get to ledge. I feel like reacting before he thinks your going to move is the best idea. It's basically mind-games. Try to neutral getup then immediately jab, if Snake doesn't expect this option, his u-smash will be canceled, or whiffed. Try quick options to nair or jab to catch Snake off-guard.
Mario