The tank is 75gallon long.
I've never had any issues raising them together. It depends on the over all temperment of your tank. I'm confident it will be fine.
With respect, raising them together doesn't prevent aggression later. If you raise similar sized fish from young, they will naturally establish a dominance hierarchy with very little aggression and without you really noticing.
If, however, you raise a smaller fish (your JD) with larger fish (Angels) but the smaller eventually catches and surpasses the larger - as yours will, then the JD will suddenly be in a position of dominance and may go too far, especially if the angels try to defend their dominance.
And if I may, if the JD is being bullied by the angels, the temperament of your tank is semi-aggressive. Even if not, cichlid tanks are never calm. It is Cichlid nature to establish dominance, and a JD is not going to accept a smaller angelfish being dominant. As someone said, teeth vs no teeth and long fins is going to be highly unpleasant for your angels.
You may be lucky, every fish is an individual and you may find that your three happen to work later: but being confident of it being fine in a cichlid tank, especially one as imbalanced as this at adult sizes, is a little naive. I'm not saying you should take them out now or even necessarily later, but it is something you need to keep an eye on and you need a contingency plan: at the very least have a tank divider on standby to prevent deaths while you re-home the JD or Angels.
Your JD may be fine with the Angels later due to never thinking to challenge them... but if he isn't, the situation will change rapidly, probably overnight. One day the Angels will be keeping the JD down, the next he will decide to fight back, they'll lip-lock and then suddenly you'll have a JD bullying a much more vulnerable Angel.
And I'm sorry, but it is not pessimistic to expect aggression in a Cichlid tank. You currently have a small severum, a small JD and two non-adult Angels. Cichlid aggression changes dramatically as they get older. A young fish will have no territorial behaviour, an adult one (particularly the size of a JD) may decide it wants an entire 75G tank. Fish aren't people or dogs, they don't become friends with the fish they are in with, nor learn behaviour: they get to "puberty" and then it's all instinct and individual temperament. You don't know the temperament of your fish as adults, only juveniles.
I know how aggressive people can seem on forums regarding this sort of stuff: I'm really not trying to be a dick or tell you you're doing things wrong, I'm just trying to help you understand that just because things are fine with Cichlids in a community now, as an adult they can change dramatically: peace now is no indication whatsoever of later behaviour.