Question 1 - Front
Placing Ad in the back row guarantees you to foul. If you place it in the front, you can still hit 2-pairs or even trips on your last card to avoid fouling.
Question 2 - Back
This is a very close placement and I would certainly say that the front and back row choices could BOTH be correct. First, let's all agree that placing Jh in the middle is the worse choice since it does not provide any royalty options.
Refer to Chart: