I"m not gonna repeat what others have already said, though I TOTALLY agree. So let me add some new thoughts.
The GT and EBJD will get creamed first because they're weaker than the others. Then the regular JD will start getting whipped because it grows a bit slower than the other fish on your list--so does the GT and the Festae.
A 75 gallon tank seems like a decent size tank to you because because you've seen lots of people do 55 gallon reef tanks to start. Tank size is totally different with CA cichlids. Tanks that you think are unnecessarily big--they're not.
I think if you want to keep several large aggressive fish, you need to look at a MUCH larger display tank, and use your 75 gallon as a grow out tank. I use a 125 gallon to grow out fish, and it's a little small. Most people here will agree that their tank is a little small, or they could use just one or two more.
You need some kinda grow out tank because these fish grow at different rates, and then slow down a lot at 8-10 inches. So if you start with a crowded tank of 2 inch fish, some will outgrow others then kill em. While your GT has grown an inch in 3 months, your Dovii will have grown 3 inches. So now, a 5 inch fish is gonna whip a 3 inch fish. Think of a grow out tank as a frag tank, but for fish.
In general, I'd say Amphilophus have the most personality. Some big Veija have great personality when they're adult, been around a couple years.
You're gonna really like freshwater tanks, though. If you do a sump and a drip, you'll never change water. No salt, temp swings are no big deal, MUCH less testing to do, no RO/DI water needed, you'll never dose anything. FW is way easier.
And there are LOTS of fish NOT on your list--Zonatus, Trimacs, Argentea, Bocourti, V. Bifasciatus, Carpintis, H. Pantostictus, Nosferatu species.