A few thoughts. Bring two pairs of synthetic socks, preferably that cover the ankle. There’s a little bushwhacking and the approach is sandy so the change of socks feels nice. You don’t need the the 5.10 Canyoneers. I wore a pair of approach shoes like these (link) and they worked extremely well but then again they have good rubber. Two ropes are necessary and ask your partner to use his because they will be dirty when you’re done. Much better to abuse his ropes than yours, right? Rappel gloves or a pair of work gloves are clutch. They will keep your hands clean and when you inevitably fall into a cactus your hands will appreciate the protection. I had actual rappel gloves while my buddy had work gloves. The work gloves were sufficient but I could manipulate the rope and scramble more easily in the rappel gloves.
We followed Tom’s Utah Canyoneering Guide for Behunin Canyon and it was spot on. (link) If you get an early start you won’t get caught in a bottleneck at the first rappel station. We left at 9 and we were the last party to arrive at the rappel station. If you leave early and move efficiently the route is easily doable in half a day.
Unfortunately the pictures above are not in chronological order. The pic with the two guys setting up a rappel is the first station. The traverse to get there is a little airy and it might spook a noob.