LIS-IAD flights will be operated by the A321LR. The seats you are interested in are now called Economy Comfort. You can find the seatplan of the A321LR
here and the features of the seats, as well as the prices and conditions for booking the seats can be found
here.
The OP is probably looking for the seats in red, seen in your first link (rows 6-12). As to the second link, I bought my flight first, firming up the dates to then reserve my hotel in Paris (as I am flexible on the dates). I then went back to TAP and after considering my wife's preferences, bought the seats for the A321LR (EWR-LIS) and the A 321 (LIS-ORY). If I recall correctly, the cost is not exactly the same as the info on the second link.