I say too late because you've bought it. I don't know how many tanks you have but one should always research about their fishes before buying. My impression was that you bought the 4 on impulse, otherwise you would have asked the questions before you bought them.
I'm sorry you've lost one gourami. It's unclear who is missing half their tail in your post. Again, angelfish are cichlids in general they don't play nice. I don't have any personal experience with them but as juvenile they are ok in mixed group but as they grow bigger they fight each other unless they are already paired up. That's why people often recommend getting either 1 only, a proven pair, or a large group and return the ones that are not paired up. I also hope your water chemistry are ok, and you haven't lost your fish because of a mini-cycle.
Forums are in general a very good source for info. Most of us know a bit about fishes either from what we've read or from personal experience. I'm not being negative or try to berate you. It's more of a reminder that next time you should make sure you have everything in place before getting your new pet. Trust me, I've been there too!
Good luck to you and your fishes.
Adrian