Thanks for the interesting questions.
When looking at the Bose F1 812 and the 8 drivers on the baffle, a few questions come to mind.
1. Is this a "true" column array sitting in front of a 12" woofer?
Yes it is a column of 8 speakers in front of a 12” woofer.
2. Does the Bose F1 812 carry the benefit of reduced drop-off over the listening spectrum, similar to other Bose column array units?
While it has properties like drop-off reduction of a column array, it’s effects are not going to be as pronounced as the L1’s. You will have the most concentration of energy when the array is in the straight position.
3. What exactly is the purpose or advantage of changing the EQ whenever the shape of the baffle is changed
When the array is in the J or Reverse J position the EQ change is adding a little high frequency energy to compensate for that spreading of energy. In the C position and it adds even more.