Im going to upgrade, thats like a grow out tank with no tank to put in when they are fully grown. Ill upgrade when it is neccesary. Recommend sizes of the tank that is suitable for adult versions of these fish(they all get up to 5 in and the common pleco (24 in.). Im not going more than 40 G
if it says ornament, it's fake. dont get wood at petsmart, try your best to find an LFS that actually cares about their fish, they'll probably have good driftwood. or you could also do some mopani wood.
pleco with malawi cichlids...nooooot a good mix, just sayin...
Tank size depends on the species you want to keep.
Larger mbuna or peacocks really need a 75 or larger. You can keep a few dwarf mbuna species in a 55, but the larger footprint of the 75 greatly increases your options.
Common pleco's will eventually be cramped in anything smaller than a 6'x2' tank. They are actually a fairly active fish, though most often after the lights are turned off.
The auratus and zebra are really aggressive species, the auratus in particular. Male auratus look like females until they mature, then they claim about a 4' territory and usually kill anything that doesn't get out of their way.
About feeding that pleco, all mine seem to like zucchini slices the best. I boil them for a couple minutes and it softens them up and makes them sink. I also agree with everyone's advice. Try and take the common pleco back ASAP.