We have pretty well gone over Bonaire the last couple of months so do a search and read the comments. If I understand a 7/5 correctly (7mm and some 5mm neoprene),unless you are super cold natured I can't see any need for that. A 3mm shortie is more than most need. The water temp does not change that much over the year. You did not say what time you are going but we only dive fleece (polartec) in June. During the day a skin is all I need but the fleece helps reduce the cumlative effects of multiple dives. A bennie cap also helps with heat loss if you are diving 3-5 times a day.
Leave the jewelry at home, it's just a smart thing to do no matter where you travel, in the US or out....Do you REALLY need it diving? As for the crime on Bonaire, its not nearly as bad as some would have you believe. There is some petty theft, mostly by kids snooping in vehicles. Just don't leave anything of value in vehicles (and don't lock them- windows down is best) and you will be fine. I worry a lot more about the airlines losing my stuff than it getting stolen on the island.
A couple of swim suits, a couple of shorts and 4-5 T-shirts is all you really need. The atmosphere is casual all over the island.
Not sure why you are using Bon Bini Divers instead of the shop at Capt Dons but BB is a nice operation and I have not heard anything but good about them. They are located at Lions Dive, next door to CD's. Personally, I would use the shop at the resort I was staying at, it's just easier than having to go from one place to the next, esp if you are boat diving.
If you enjoy a slow pace, good food and friendly people, you will enjoy Bonaire. If you can't slow down and enjoy the flowers, you may not enjoy yourself. If you want to see big fish, sharks and ship wrecks you will be disappointed. If you enjoy a slow dive with tons of med to small fish and reef creatures, you will enjoy the diving.