(Urgent please help) Perplexity effect

Hello, I need help.
So I want to create a potion effect that when it is active it shifts the player's keybinds (forward becomes backwards, left becomes right and jump becomes sneak and vice versa)

This is for MC 1.12.2 and I was wondering if 

1) Is there any way to do this currently, if so how?
2) If there isn't is there a way to add potion core effects into MCreator as a plugin or something

thank you