I personally think the aggression in jardini are overrated, they are quite placid IMO except when challenged. The only time my toga has told off any fish was when the dovii kept nipping him and even then the jar just gave a little warning bite then swan off. You will be fine providing your current fish don't piss off the jar too much.
If you want fish that will live in harmony together then tank busters aren't for you. Of course big aggressive fish will fight with each other, its in their nature.. they won't go around giving hugs to the other fishes that's for certain.