Thanks for playing. Interesting suggestion to make 12 before 11, but I do think 12 is more advanced. So I think maybe a better way is to lock up all objects in 11, though I'm afraid that will trivialize the puzzle.
Regarding 10, it's not related to 11 and further. Interesting insight about slow doors, especially given these doors were a clutch solution to make the player forced to make a permanent change.
Also grabbing is indeed a secondary mechanic, that was introduced to ensure you can't get soft-locked by pushing a box to a corner, that players liked so much, I improved and polished it so much it almost became the main way to move things