I think I said in 1 of your threads, I'd go with female bns, no males, or just 1 hiding male & no females. But with the clown pleco & bn(s) you want to have several hiding places so each can choose, 2 plecos, at least 4 "caves"; 3 plecos, maybe 5 or 6+...at least some should be wood, say half or more, just a guesstimate. & as I said, female bns are not as territorial over caves as males; clown plecos need a daytime hideout. They're half the size of adult bns & will lose any battles over caves...especially with a bigger male bn...they all have pectoral spines & can hurt each other if too provoked...again big bn, longer spines & larger body mass = better able to defend his chosen nest.
If you want to see your clown pleco more, try having the tank lights go off a couple hours before room lights go off (& you go to bed) & feed a bit after tank lights go off...that only works a little, many fish will eat in "twilight"...I don't think corys miss food at any time, lol. They feed by "smell" more than by sight. It's all a matter of fine tuning for your tank & fish as to what & when you feed. I use cheap timers to control lights, feeding is a bit more hit or miss.