Some of the notable choices I see here would be the Midas Blenny, Anthias, Flasher wrasse, Leopard wrasse(can be difficult to acclimate so be sure you and your system are up to it), Yellow coris(which is not a Coris wrasse at all, not only that but you already have a lot of yellow {tang} so I would look at other choices of Halichoeres wrasses), and lastly the Starry Blenny a and or Bi-color, they will be out and about as well and make a great addition to most any tank but I would not really call them active open swimmers, even the Midas will spend part of his time sitting in the rocks
Not such great ideas,
School of chromis, never works out in the long run, most will surely die. The Six-lines seem to be more and more aggressive these days, if you get a mean one it will limit what else you can eventually put in your tank and may very well get your peppermint.
Bellus Angel and Blue jaw, as mentioned, active and not at all suited for a 90.
Hawkfish are cool but will spend theyre time hugging the rocks and rarely swim in the open, also as already stated Bye, Bye shrimp. The Rabit Fish, another too large choice that grows pretty fast BTW.
One-Spot Foxface, same category as the Rabbit Fish, will soon outgrow the 90, one hell of a herbavore though if your having algea problems.
Acanthurus pyroferus, My personal favorite. Slow growing IME but will eventually outgrow the 90. I would endorse this choice for short term but man will it ever be tough removing him after a few years.
If it were me and I knew I had the ability, I would go with some of the smaller species of Antias and the Midas, secondary choices would be Flasher wrasses or one of the Halicheores wrasse, likely alternates would be the melanurus or biocellatus.
These seem to best fit your criteria.
Theres my 2 cents.