It is the general class of the fish involved that is semi aggressive. Actually you may be surprised to know that of the ones you have listed that several fall into that classification.

The Barbs of course and the Gouramis and Bettas but also the Angels fall into that class not so much because they are tempermental but due to their tendency to be territorial.
Bettas and Gouramis are generally not considered compatible at all because they are both of the same family and as such will fight each other as if you have put two males of the same species together. They consider each other threats of a major order and the only time I have seen this work is when they are in huge tanks with plenty of cover and crossed fingers that they do not discover each other. Once they do they fixate on the other one and one or the other will be injured or die. Barbs are just cross when interfered with and do better if they have a large number of each other where they just stay together and more or less leave the others alone but again in all of these fish huge tanks make the rule. Territorial fish are vicious when they feel crowded and you do have them. You will only have a problem with the Angels if you have a breeding pair and it comes time for them to spawn and some of the other encroach on their territory, or if your pair is not a breeding pair and one or the other decides they would like to try it with the other. Then you will have a problem. Unfortunately, Angels are a lot like Bettas when it comes to breeding, they decide on the mate not us. But Angels carry it one step further and usually accept only one partner where a Betta may take more than one in their lifetime but carefully. Breeding either of these fish is a challenge and a lot of work both before and after.

Your tanks are larger so you should be okay with care but you will not be able to fill your tanks with smaller filler fish to make the tank more active. That will simply frustrate and aggravate your territorial darlings. A tank like you have is fascinating but will not be as active and quick moving as a more pacifistic tank would be. But it will be a beautiful and relaxing tank to watch when you want to just take it easy. I wish you the best with it and look forward to your posts and statements. I think I will learn a lot from your tanks. Thank you for joining.

Rose