You can! The fastest way to do this when you die and don't have a backup available, hit plus to bring up your pause menu then -> files -> load -> click the file you were on and select a character. It'll bring you back to the last autosave and you'll have your catsuits!
Big shame that 5-1 exists cause if it's for 3dw, then you are stuck on a Plessie autoscroller, so that's as far as you can go.
Even if you die on a level, if you press pause, go to files and load up the same file you are on, you'll spawn with your cat suit back
The game is really easy to run. So long as you have a rough knowabout of where pokemon are located, the run is simple to complete. Deathline's route in guides will help ya a lot to get going. They also have a tutorial guide in resources for extra help.
Needs a little bit of a retime but ill take sub 53