To answer some of your Q's I'm no expert so please anyone correct me if I'm wrong.
Rows 8/10/11 are extra space seats, row 9 was removed a few years ago to accommodate this. 3x3 layout (ABC/DEF).
Row 12 ABC I believe the door bustle restricts legroom space and that's why TUI don't sell 12 A as extra space.
Rows 32 3x3 (ABC/DEF) are all extra space. As should be 2DEF at the front.
Correct with the exception of 2DEF.
On all of TUI's 757's 2DEF has a bulk head wall in front of it, so although no seats in front, there's also nowhere to put your feet as you would if there were seats in front. Leg room is slightly better but not massively, so these seats aren't sold as extra space.
On some 757's 1BC still exists but are never used, which means 2A has more space as no seat in front.
On some 1BC doesn't exist and 2ABC is an exit row with loads of space.
On some 2ABC has a bulkhead wall in front of it, similar to how 2DEF is setup.
12DE are also great seats for a couple. 12F doesn't exist on any of the 757's