Quick summary so far (please mention any errors): all the existing A321 aircraft (also known as A321ceo) have now been densified to 218 seats in total. The various seat plans that exist online for the 205 seat version are now therefore redundant. All the seats are Pinnacle, so the main type used on LHR's A319/A320 and non BMI Gatwick aircraft. CE has tables. Most of them have power but there there seems to be some exceptions. Coming in soon are new A321neo, with 220 seats, with the thin seats from row 14 and back rather than Pinnacles, but they aren't in service yet. You can tell which is which since row 9 on neo has 6 seats across, on the legacy densified A321 it only has 4 seats.

For the A321ceo: I see a lot of mentions of rows 10 and 24 on the densified A321ceo and here are some photos from G-EUXK, which has seat power. Bulk head seats (etc) have power under the seat, but most seats have the power in an easier location in front, it's just USB. The power hasn't been commissioned yet, so unlike the A320 with power, it's not yet usable.



This is 24A, with a proper window now, though it is set slightly further back than optimum. Still, a lot better than the predecessor. 24F is identical. Heaps of leg room, fixed sides, table in the side. 24B and 24C don't have legroom advantage.



And this is row 23, a pair of seats, also with plenty of leg room.



This is row 10 (the bent wings was my device to make sure I didn't mix up the rows), and it's quite similar, but the window is perfectly places here. All row 10 has good leg room.




And from closer up 10A. There is no obvious difference with 10F, other than that the crew member has a seat by there for take off and landing, ditto 24F. That doesn't affect the leg room by very much.



Row 9 is just a pair of seats on the ceo but it doesn't have any leg room since it's part of the main block ahead, however 9B has a bit of sideways space. 9E doesn't due to the crew seat.