The rams would be fine at that temp, but i don't know about the gourami's. If I were you If you want that Discus to do well, jackup the temp all the way to 30 C, that way you could avoid some bacterial infections such as ICH, also at this temp your DIscus metabolism would increase and that could get him to eat whatever your feeding him..just my 2 Cents....
GoodLuck...