We stayed at BelMar a few years ago. It's very clean, quiet (if kids aren't in the pool) and the house dive is good - not great - we did it twice. It's the other Buddy dive shop so you can use the Buddy drive-thru for tank exchange when shorediving the north end of the island.
Nice condos, full kitchens minus oven and all of them have patios with an unobstructed view of the setting sun. It's a very compact property surrounded by houses so pretty quiet at night. If you have a ground floor condo, there's a dive locker outside your back door, upstairs gets a locker at the diveshop on the south end of the property. You park 30' from your door and shoredive tank pickup is at a little fenced area by the diveshop, when we were there your condo key opened the public areas of the diveshop for tanks, Nox analyzer etc. They also stock tanks on the divedock.
At different times I've heard that Buddy's either sends a boat down to BelMar or you have to drive up there if you're planning any boat dives. It's about 10-15mins. between the properties.
BelMar is located in Belnem far enough south of the airport that I never heard a plane - yet close enough to be convenient.
If you use Google Earth, PM me with an e-mail address, I've got all the major resorts - nearby divesites, piers, the market and some restaurants located on a .kmz file I can e-mail. Gives a really good sense of the distances involved.
The biggest downside to BelMar is a total lack of restaurants within walking distance. Afaik there still isn't even any in Belnem. The closest is probably at the Plaza resort which is a 2min. drive past the airport and around the lagoon. Or 2 more minutes to downtown Kralendijk. But you're literally 2 minutes to the south dive sites from there.
Port Bonaire is a nice condo complex also, slightly closer to town, but they're in the flightpath and there's a couple of real early morning KLM flights. We drove in there but I didn't see any advantage to it over BelMar.
Buddy's looked nice also when we were there but the bar gets loud if they're booked up - which is pretty often, it's a popular place. And it's bigger since they took over the Lions Dive condos next door a few years ago. Not to fault it, but you mentioned wanting a smaller place.
They were building Den Laman when we were there so it's the newest property of the three. It also has the advantage of being on Bari Reef, which has the most counted species of fish in the Caribbean. Bonaire Dive/Adventure is there and they do nature programs in addition to diving.
From what I recall, Eden Beach should be the next property south of it. So 2 minutes between all the dive sites at the resorts in that area. I think Eden Beach is the Front Porch? site, Den Laman is Bari Reef and Capt' Don's sits on LaMachaca with Cliff just to the north - both are doable in one dive. Buddy's next door to them also has a good reef, I just don't know the name. Since the resorts sit perpendicular to the water, it's easiest to drive in and out of each resorts entrance. All have full facilities, we dove all of them except Front Porch in one afternoon. Capt' Don's charged $5pp to use their lockers/showers.
The only resort with any sort of beach of the three you named is Eden Beach. It's pretty nice with a beach bar(Bongo's?) fronting the water. We didn't see inside a condo though. But due to their orientation, most would be a short walk to the water - some would even be view obstructed from what I remember.
BelMar sits about 10' above the water on ironshore. Walking distance down the street is the Bachelor's Beach divesite but it's not much of a beach. I don't think there's any beach at Den Laman either, but it's a real short walk down to Eden Beach. I think you walk along the waterfront but I'm not sure.
enough rambling...