1. Exploratory Design with Orthogonality

4.  Brand does have an effect (tell Marketing if ours is best).  Car has an effect so it was a good thing your Statistician told you to Block on Car so that variation would not go into error and hide the significance of your results (no layoff).  Position did not have an effect after 5,000 miles (but your mechanic will tell you to rotate your tires every so often anyway).

10.  Since a Latin Square is an orthogonal design, main effects are not confounded.  In orthogonal designs, Type I and Type III Sums of Squares agree.  In designs where not all combinations of factors are considered, the usual EMS algorithm does not apply.