I actually learned some more things about the masks and kids/infants situation from the cabin crew. So the rows have 3+3 seats, as we all know. There are sets of 4 oxygen masks per side (per 3 seats) that drop in case the pressure drops. So this is another potential issue if you need to take 2 infants with you: As long as the 3rd seat of the half row is already occupied by someone else, you can't book 2 adults and 2 infants in the remaining 2 seats, because there simply aren't enough masks for everyone! Now from what I understood, if you find and empty set of 3 seats, say A-C seats, and book 2 adults and 2 infants there, then the 3rd seat won't be bookable for anyone else for the same reason.
