Answer:
3rd position- Both feet are turned out, but with one of the heels touching the other foot's instep, halfway along the foot.
4th Cuaze- Feet are turned out, one foot is about a foots distance away from the other, the toes and heels are oppositely in line. (It is like 5th position except the front foot is slid away from the rear one).
4th Ouvert- (Not as common but still a position) Like 4th Cuaze, but the front foot is moved outwards to the side slightly, so when a grande plié is demonstrated, both heels are able to stay on the floor unlike 4th Cuaze when the heels are lifted. It is like 1st position but both feet slid out with about a foots distance between them.