Only one goal from a centre back all season (Hughes). Drameh, Coyle & Jacob were the only other defenders to score.
Bedia, Simons, Oscar & Longman all scored and then were moved on at various points. Like you say, 11 players scored 1 and 3 more scored 2, so that's 15 out of the 20 different scorers.
Alzate, Joseph, Omur, Mehlem, Lincoln, Barry & Amrabat were all midfielders / attackers who didn't score in the league either. I know a couple of them barely played, but it shows the churn. Then you have players like Millar, Belloumi and Matazo who all played a few, scored then did ACLs, and Zambrano who played a few, scored and got banned.