Reina
Kelly Carragher/Skrtel Agger Enrique
That, IMO, is the best defence we've got. Johnson would have a tough time reclaiming his place back. Flanagan has been impressive to me but he's still young and therefore can be in and out of the side. Wilson and Coates can come in at CB for some games like in the league cup or when it matters. Aurelio deputises Enrique with Jack Robinson, also with time on his side, stepping in when needed.
Two primary RBs (Flanagan and Johnson), three primary LBs (Enrique, Aurelio, Robinson) and 6 primary CBs (Kelly, Coates, Agger, Skrtel, Wilson and Carragher) is more than enough and this leaves me happy with the defence as Johnson and Flanagan can play either wing or in a back 3, Kelly can play CB and Wilson/Skrtel/Agger can play as LB/RB and LB respectively when urgently needed.
The front 6 players, IMO, don't matter to me when attacking. Kenny likes to pass and move. Everyone of the six inter change often as we have seen in previous games but obviously, we need standard midfielders and attackers.
Henderson, Downing, Adam, Lucas, Maxi, Gerrard, Spearing and Shelvey are primarily midfielders and in recent games this season, we've started with four in a 4-4-2 and about 3 or 5 in a 4-5-1(4-3-3) formation.
Our strongest would probably be a side with Gerrard, Lucas, Adam, Downing and one more for a 4-5-1/4-3-3. For a 4-4-2, Suarez/Kuyt/Bellamy and Carroll take those two spots but of course, Suarez has to be in there.
As I've said, with the ball, the formation does not matter but when defending .. it should be something like ... (depending who is on the pitch)
Lucas/Spearing Adam/Shevely Lucas/Spearing Adam/Shelvey
Henderson/Kuyt Gerrard Downing/Maxi or Gerrard/Henderson/Kuyt Downing/Maxi
, just realised how messy that looks.