Ah, so it's still a mono-type team as you are using 1 type but can have secondaries.
My suggestion. Scrub the water. They are weak to very common attack types. Grass, Electic, Ghost for Bro and Mie. It'd be easier to just break down.
My suggestion would be either use a rain dance, or choose a different type. Maybe Ground. Ground has good resistances and 1 immunity, and has access to many secondary types.
You could also run Steel as it has an immunity plus a lot of resistances as well.
But I have to go now, good luck with your team building.