The most likely blocks would have been the blocks that City use for away fans in Level 1 but they already have City fans in them (our singing section is in them). They are blocks 113 and 114.
In the Champions League games, away fans often get a block of what they call premium seats which is on Level 2 above the half-way line. The problem would be that the game has been onsale for home fans for some time.
The sales which you have posted don't seem to square with the tickets allocated to Vale so I think you might find that Vale audit their remaining seats and then put the remaining seats on sale.
The top picture is the overall picture for City at the moment, and the image below is the seats of one block (114) in the away end, and you can see that it's nearly sold out.
I doubt City regard this as a high-risk game so if they can accommodate more Vale fans, I am sure they will try but I don't think there are any big blocks of spare seats. I'm sure it will become clear over 48 hours.
