You may well find the Betta does not get along with the other fish, they can be very aggressive toward other fish, especially fish with fins similar to theirs.. longer ones, need not be as long as the Betta's are. Some fish will be ok, but many will not and you should be prepared that you might have to keep the Betta separately if he can't get along
The Otos and the shark are not a good combo. Otos are small, inquisitive and busy, all over the tank, where the sharks can become extremely territorial, so the Otos may be bullied, which they won't handle well. The Betta may not care for the shark either, and even the cories will likely be bullied by the shark. Pretty fish, but not the best community fish, IMO
EBRs can also be a bit challenging to keep. Lovely fish, but not the best fish for a beginner. Might want to wait awhile before you get fish like that. They also prefer a mature tank, not a newly cycled one, another reason to wait and get the tank going and settled before spending the money
And I feel like I am raining on your parade, but the butterfly fish can be very aggressive too, territorial, and with fins like that, the Betta is going to hate it, and it's going to hate the Betta, I'd think. They also can jump, almost fly, so a tight cover is needed over the tank.
You need to research the needs of the species you want to keep, not just how many you can fit into the tank. Many fish get on well together, but you happened to pick a few that don't.