So it seems like we're sticking with the 4-4-2 / 4-2-3-1 hybrid for the time being.
It's honestly quite confusing to watch at times because I'm never too sure what formation we're playing and when. The only thing I'm ever sure of is the back 5 and Lukaku playing predominantly as a central striker.
According to the club's twitter we had the following set-up against Chelsea:
Howard
Coleman Stones Jags Galloway
McCarthy Barry Besic
Barkley
Kone Lukaku
It must be noted that McCarthy and Besic aren't playing as "wingers", they are the wider of 3 central midfielders. Though I was confused by the lineup, I didn't begin fuming when I saw Naismith lining up to replace Besic, he's more suited to playing as a centre-mid than Mirallas, Lennon or Deulofeu.
Naismith isn't the most positionally disciplined player, so he would often interchange with the 3 guys ahead of him. I do think that is something Martinez encourages though. Especially considering we're used to 3 players behind the striker who often rotate.
The above formation (swapping Besic out for Naismith of course) is what I believe we were playing when we had the ball. Out of possession I'm confident we go back to our usual 4-2-3-1:
Howard
Coleman Stones Jags Galloway
McCarthy Barry
Kone Barkley Naismith
Lukaku
The evidence for this being Naismith and Kone doing the covering on the flanks.
When Lennon replaced Kone, I think we made a permanent change to our usual formation in an attempt to see the game out. I t ended up being a great change with Lennon being involved in our third goal on top of his usual defensive work-rate which endeared him to many of us on his loan spell.
I think I said something similar when I originally made this thread post-Southampton, but I guess if it's confusing for us to see exactly how we've set up, then perhaps the opposition are having a hard time, too. Obviously, I wouldn't advocate us switching formations multiple times every single game because I think that would only confuse and disorganise our own players but certainly it's good to be flexible. The Swansea game will be interesting because they are a team that likes to play with a lot of width, giving a case for any of our 3 out and out wingers to start but with the form of Kone and Naismith it would be harsh if either of them were dropped.