Thanks for the replies everyone! I'm appreciating them alot and the feedback on the various species is great, so thanks again!
Here are my concerns with the aforementioned species:
GBR: I know nothing about them so I Googled a bit and they are beautiful fish! My temp may be a bit too cool for them as they seem to like warmer water. I don't have a cave in the tank for it to hide it but I could provide one. But if it's a mid-dwelling fish I'd rather have something that's going to fill out the top level as the Corys are mostly bottom and the CPDs are mostly bottom although they venture upwards sometimes. I'll do some further research on these though, thank you.
Dwarf Gourami: I had initially considered this for a centerpiece a few months back while cycling and researching stocking. I've since seen a lot of people having problems with them though. They are beautiful fish (the blue sparkling ones especially, but I've seen the honey ones which are also very cute). A bubble nest wouldn't bother me at all; in fact I think it would be awesome to witness (in theory at least lol). I'm guessing I would just get one either male or female so that they don't fight?
Betta: I'm really torn on these fish. They can be very pretty from what I've seen online, but most of my exposure to them in person is seeing them in small bowls at the pet stores and they aren't very striking to look at (although in fairness they don't have room to display either
). My concern with Bettas would be either it being nipped at by the the other fish given its long fins or/and it picking on the CPDs given how small they are.
The issue is anything I get is a gamble given that each fish has its own personality. If need be, I have an extra 5.5 gal tank that is not being used (I was considering cycling it for African Dwarf Frogs) so if I put something in the tank that doesn't go, I could potentially take out the CPDs and give them their own species tank in the 5.5 gal, or the Betta if I got one. However I'd like to avoid this if possible and I'd feel horrid if I got a fish and I had to return it due to aggression. Also the sides of my tank give reflection, so I'd be worried that the Betta would be constantly flaring at itself.
So right now, I'm still undecided.
More feedback would be great. I'm leaning toward the Gourami first, the Betta second at this moment in time.