Free Kick after a Fair Catch
 

It's 4th and 8 from A's own 3 yard line. A is in Punt formation. It's a windy day and A punts from there own end zone. The Ball travels to A's 7 yard line where B1 signals for a fair catch. B informs the officials that they elect to free kick the football from the 8 yard line. So after lining up the kicking team at the 8 yard line for their free kick, where would you have the opposing team line up?

Same as any other free kick. Ten yards from the ball. Which would be inside the end zone.

Football Fundamentals (pg76) V.2: Free-kick lines are always 10 yards apart.

Except that the free kick restraining line always has to be in the field of play, therefore by rule the line cannot be beyond the goal line.

Roy, this is an NF thing... the 10 yard zone under that code will indeed extend into the EZ if that be the case.
Wasn't always that way, but is the fact of life .

Roy do you have a reference for that?

The free kick lines are always 10 yards apart, even if its 9 1/2 yards deep into the end zone