Softies are generally easy to keep. Any type of leather should be fine but you dont want to keep it where the flow hits them dirrectly. Zoanthids and palythoas are not that difficult to keep and they are beautiful, they have become very popular these days. Anemones are light demanding invertabraes, i think you should be fine but not as easy to keep as the corals mentioned before. You can keep a ton of things with the equipment you have, and if you keep up with water changes and have good husbandry then you might be able to keep almost anything.