Hope you have a great trip. Yes, a few players from both teams will often stay around for a bit after a game, if you go to the front you have the best chance. They always seem happy to have a picture taken with the kids and I am sure adults as well. As said, either side of the tunnel is the best chance, I have seen them go all around, but not always. I am pretty sure that you could get into block A after a game even if seated elsewhere, but sods law might mean you get stopped for some reason, unlikely though.
The other chance to meet players is at the bottom of the steps outside of the atrium at the south end (dual carriageway side). The players go in under steps there and you can see them go in and out from there, obviously they are more likely to stop on the way out. The way in is more a cheer them in thing and they sometimes publish a time frame when they arrive. Injured players and family often go in and out there as well, my daughter's screen saver is still of her and Cips when we saw him on his way out and asked if he would mind having a photo, he couldn't have been more patient with us.