everything sounds fine except perhaps the angel. If you have to have a large species angel go with something that stays a little smaller like an Annularis or Majestic. Add the royal gramma before the tangs, blenny and angel. In a tank that size makes no difference if you add the clowns or gramma first. Tangs, blenny's and angels MUCH more likely to harrass the gramma if added last then the other way around (its a gramma not a psuedo). I would do it in this order: gramma and clowns 1rst at the same time (should be no problem in a cycled 125), lawnmower blenny, hippo tang (if thats the tang otherwise the powder brown first), powder brown and angel last.
I've had all these fish your interested in at one point or another and together except the angel. If they are anything like dwarf angels definately add last. Right now I have hippo/powder brown together. Before that I had the hippo with a lawnmower blenny, royal gramma and one false perc. I had those in this order false perc,LM blenny, royal gramma and hippo added at the same time. Dont think for a minute a Powder brown cant get nasty with new comers. I had to take mine out for a week when I added my anthias and midas blenny. hope this helps. Hippo's do a lot of shadowing initially but no real aggression unless they are pretty large.