Both formations of the ninjutsu end with the same symbol
Katon (2 mudras) will always end in Ten
Raiton (2 mudras) ends with Chi
Hyoton (2 mudras) ends with Jin
Huton (3 mudras) -- Ten
Duton (3 mudras) -- Chi
Suiton (3 mudras) -- Jin
So even if you mess up the initial button press, which is likely to happen since they threw four new ninjutsu at you anyway, you can still save it to the one you want.
The first mudras don't matter as long as you end with the proper one, and have the right number in total.
It is good to get them in muscle memory to begin with, but if you get lag or something you can think on your feet to avoid getting the bunny