The correct answer to the Half Twisting Helicopter quiz is it’s Legal in Level 2. The top person is twisting simultaneously on the horizontal and vertical axes and the base in blue maintains contact with the top person during the entire transition. The definition of Twisting Stunt says:
Simultaneous rotation on the Vertical and Horizontal axes should be considered separately, not cumulatively, when determining the degree of twist.
The amount on twisting on neither axis exceeds a 1/2 twist, which is the limit in Level 2 and the base in blue maintaining contact with the top person makes the skill a regular transition instead of a release move.
This ruling and explanation are based on the 2016-17 version of the rules dated August 31, 2016.