Congratulations on your AR91 acquisition. Did you know that the grills for the AR92 and AR91 are interchangeable. They also used the same boards, just slightly different capacitor and resister values. I replaced the binding post with these inexpensive insulated post from parts express.
https://www.parts-express.com/Mini-Insulated-Binding-Post-2-Red-2-Black-320-3375?quantity=1
The banana plugs hang out about 3/16 in. ,but are very secure. On more traditional AR speaker binding post I took Adamas approach with ring connecter adapters.
As far as recapping, the recommendation of using quality NPE's is spot on. I used all NPE's except for the 4uf which is a Dayton Precision Poly. The Mundorf Plain and Janzen Smooth NPE's have been discontinued, but if you look around you can find other quality electrolytics. I also replaced the resisters with Mills resisters which have become very expensive nowadays. If you original sand cast resisters test fine, I would just reuse them.
If your 91 boards have the Unicon capacitors you might want to keep them. Mine didn't.