i have had several pairs of rams, a pair of apistogramma bitanaetia, a pair of apistogramma pulcapanesis, a pair of apistogramma caucatoides, and a pair of curviceps in with discus with no problems(not all in the same tank of course

). they ignore each other for the most part. the bitanaetia did get a little aggressive when they bred but the discus would just swim right past them sending the male apisto right back into his cave. i personally would skip the cories and add a school of about 15 schooling tetras like cardinals or rummynose. it adds a little movement to the tank when the discus are just floating around and they make the discus feel a little more secure. chain swords make a great foreground plant as do many of the crypt varieties. i like banana plants also since they have leaves ranging from brilliant green to reddish and they send leaves to varying heights in the tank. crinium makes a wonderful background/cover plant. sorry for the novel. HTH