As an update to this, I cross referenced the seeds with the positions. It looks like the last set only has 4 pokemon in it. This also means the first set starts in position 2 (row 2, column 1). The pokemon are generated vertically in batches of 5 as I previously stated. So we can only extrapolate 419/426. No idea if the 5th in the last set was in the party, or looped back around as the first one. Otherwise there could be up to 426 total mews, of which only 419 can be determined.