We're flying to Athens in ET on Sunday on a -20D with a lap infant and a 3 yr old (4 passengers including lap infant) and there is no B seat in row 6 on the seat map.

I had moved our seats to 6A, C & D. Will the B seat be completely blocked or could they take the divider or whatever large armrest/blocker is out? That would be ideal to put our younger daughter in or should I go for seats 6C, 6D and 6F and hope that nobody takes or gets assigned to 6E? The seat map for ET looks less than 50% full at this point.

Is there a limit to how often you can change seats? I had gotten a confirmation when i moved up from a row further back in the plane, but it I get a message that it can't confirm the changes when I try to make a change now. I am trying to move the 3 yr old from 6A to 6F which would leave 6E empty if that might be causing any issues.