this is the stocking right? can you tell us the dimensions of the tank (i.e. width and height as well so we can work out the total volume) please? lets be totally honest here, i think you have bigger things to worry about than the decor, although to answer your question virtually all fish will appreciate some decor, don;t fill it up loads so there is swimming room but one of the best ways to avoid agression is to have tall things in the tank which break the line of sight, if fish can't see each other then they won't attack, so you need to set things up so that they can get out of the line of sight of each from time to time.
however
1x Red Tailed Shark.
1x Golden Orph. (Was feeder fish but servided) - needs a coldwater pond, find a neighbour with one and give it away if possible
1x Green Terror. - may be too agressive for the other fish
1x Pleco. - what species, some may get too big for the tank, some will be small enough to become a target for the larger agressive fish that you have
1x Red Jewel Cichlid.
2x JD.
2x Oscars. - are these a proven breeding pair? if not then you're storing up trouble for down the line, once they hit sexual maturity (around 1 yr to 18 months old) they'll kill each other
3x Firemouths.
4x Angels. - will be eaten by the big cichlids once they grow up
4x Kribs. - will be eaten by the big cichlids once they grow up
i think you need to make some changes to your stocking list