I think that is pretty much it. The AF minis are either midshp or have aft balconies. The AG locations are generally a little less desirable (more ship motion). Now when an AF and AG abut I think you might be hard pressed to say the AF is worth more than the AG, but I guess the have to draw the line somewhere
All I ask is a tall ship and a star to steer her by; John Masefield
Carnival: Glory 2004, Destiny 2008, Splendor 2009, Freedom 2011, Valor 2012, Dream 2013
Celebrity: Summit 2011
Princess: Ruby 2010, 2014, Caribbean 2013, Coral 2014, Regal 2014, 2016
Sail Windjammer: Mandalay 2017
Star Clippers: Royal Clipper 2015
There are only 4 AG cabins and normally they are offered as a GTY special rater then dropping the price of the AFs. Booked as GTY 9 times out of 10 you end up in an AF. The rub for you NCL normally does not allow GTY bookings of 3 passengers only 2. The cabins are idendical to an AF it is all about location.