Battle 3 - Showdown at Old Corrolan Help: B3 specifically
Battle 4 - Showdown at old corollan - #6 by FrozenFlame
Battle 5 - Problem in Showdown at Old Corrolan
These are the latest posts I can find which show the battles. The monster movesets change a bit so the technique might not be exactly the same but hopefully it gives you ideas for how to complete them.