To go with oscars and an Arow you've got plenty of choices.
I'd go with severum's, have a rotkiel and a turquoise myself and they seem to get along just fine.
Also have firemouths and a convict in there as well.
You've got plenty of choices, imo the best option is to stay away from other cichlids that are named after prized fighters, devils and that have terror in their name. (I read something along those lines once and it stuck with me). Search through the site and check out peoples setups and figure out what the right fish is for you and the look you're going for.