Who are you counting as the four full backs? Because Poole seems to be needed at CB (and potentially seen as one now tbh) and I'd count Roughan and Benn as young lads.
I don't think we will but ideally we would sign a LB and loan one out. I think most of us, and potentially the club, probably thought we'd start with Bramall LB and Robson understudy - I know Bramall wasn't always flavour of the month but I think that's better than the arrangement we have ended up with, with someone with question marks as first choice and a 19 year old as the understudy. We were linked with that Towler who sounds (from rumours) like he doesn't want to play LB but it made sense we were looking at strengthening there.
At RB it doesn't seem as if Benn is ready yet and I'd count as a 'young lad' so the dream would be new first team player/Eyoma understudy, new player/Robson understudy, Roughan/Benn games elsewhere fit and firing for January or next season and two players currently for each position.
Perhaps the plan with the O'Connor signing was for Poole to play RB, in which case the left side is really the one that needs strengthening and we just have to get to Montsma regularly fit/some time with Jackson/Walsh fit. I don't think the current situation of having two slightly off the pace full backs and two inexperienced deputies is the dream though. The O'Connor signing did always strike me as a surprise early season with the weaknesses elsewhere and especially at defensive midfield but he does seem to be a more durable choice at CB than some of the players at our disposal.
I agree though it's probably unlikely we sign full backs and it's more likely centre mid + forward player in. Since Towler, not seen much by way of full back links but we've had Gilbey, the Palace winger, Diamond, the Charlton winger etc.