I feel like 12 Pokémon is enough, but you may more revitalizer to get back Yanmega for reuse. Building on others' suggestions, I think these are the changes you should make:
-3 Foongus
-4 Pokéball
+1 Revitalizer
+1 Brock's Grit
+3 Ultra Ball
+2 Level Ball
From top to bottom, I will explain my...