my future 200 gallon tank

[Chicklette]

Go with 2 Oscars or 4. If you have 3 then two will pick on the smallest one. 2 Oscars is a pretty big gamble as well but doable if the Oscars are right and the conditions are ideal. 4 or more would be best but if you go with 4 or 5 Oscars I wouldn't really add any other fish to a 210 gallon tank. 4 Oscars in one tank would be awesome though when they reach adult size

That sounds good. You should ditch the others and make it an oscar tank, you will most likley get a breeding pair out of it. But two is risky, I would get 5 baby oscars. They grow fast so your tank will only look empty for a while. That's what I would do.