I would say not for the first as it is counter-intuitive. They get it when they are skirmishing, when formed they are just acting as line troops.
"...may only be done into its front arc"
I take this to mean they can wheel on a front corner as long as they wheel by marching forwards through their front arc; they cannot wheel by back-stepping through their rear arc. Obviously, this means a unit can pivot on one corner through 360 degrees, if it wants, as the men will always be marching through their front quarter as long as they are all pivoting forwards.
BTW, on a similar subject, simply about facing 180 doesn't work in reality as the left would become the right, the back rank would become the front rank, the grenadiers would be at the wrong end of the line, the platoons would be arranged out of usual sequence and the officers, NCOs and musicians would all be in the wrong places. Command and control would cease to exist very quickly as even actions such as firing by platoon would be very confusing to troops thus arranged. An about face was actually a complicated manoeuvre which required the companies and platoons to counter-march to the other ends of the line before wheeling into position. More often, and quicker, was to wheel forwards through 180, providing room was available to do so.