How fearless is your daughter? You've been to Bonaire - how would she handle the shore entries over the ironshore with a tank on her back? You might look at Curacao instead. Most entries are off sandy beaches. Same great diving as Bonaire. Almost everyone also has an on-site dive operator, food options, showers, bathrooms etc. Compare/contrast them here:
Scuba Shore Diving Site Listing for: Bonaire South, ABC Islands
Scuba Shore Diving Site Listing for: Curacao, ABC Islands
Curacao could be easier/cheaper to get to also. All the Insel Air flights stop there first.
Curacao - a Unique Island Paradise
Off the top of my head, three properties that have everything you're looking for - nice beach, nice resort, kid friendly activities on-site or nearby, on-site operator for both shore and boat diving - additionally the last two have a breakwater out front.
Curacao Hotels | Marriott Curacao Beach Resort & Emerald Casino | Piscadera Bay
Our Resorts & Spas - Sunscape
https://www.lionsdive.com/en/
There's also about a dozen condo complexes all over the island either on a dive site or within walking distance (with gear) to one. Some have their own dive operation just for their guests also. Many have boats. I have not been to Sunscape so I don't know the diving situation there. Although both it and Lions Dive have Ocean Encounters on-site - they're known as a safer operator. I've also never dove with CSS but have been all over the Marriott except in the rooms.
Kids will find more to do on Curacao also. There's the Sea Aquarium where they can feed things and see the Dolphins. The Ostrich Farm. Sunscape and Lions Dive being slightly south of town are near the aquarium. Downtown is just 5mins. away also - far enough to miss the cruise traffic. Also Curacao has a lot of nice, wide, sandy beaches. Bonaire has 2? - 3 if you count Plaza's. And it's the only one with amenities.
A cool dive for an 11 year old would be the Tugboat. It's 17' deep and fully penetrable. If there's no ship working/tied up at the pier nearby it's also divable. I don't think it's 40' deep there either. Head out west also, we dove Varsenbaai. Seahorses at the mooring at exactly 41' (IDK how I remember that), squid at 20' and turtles at 6' along the south just off the beach. The on-site operator said they've been there for years. Boat moorings are often around 40' also so that's convenient for boat diving. We dove off Playa Jeremi - coming back in I followed the rocks along the north side. There were amazing orange cup corals there in under 10'. I dove down to 20' and it may've been more lush. I later read that Frommer's named it one of the top snorkels in the Caribbean.
I believe the breakwater out front of Lions Dive shelters the dive there. Sunscape (as seen in their photos) is actually behind one - IDK how hard it is to get out around it. I think there's one submerged off the Marriott also to help with beach erosion. They have a pretty nice beach and abut a public beach to the south. The Hilton next dooor, not so much. Plus it's been charitably called a dump here.
It seems like I'm always suggesting Curacao as a better option than Bonaire. In your case I think it might be. I actually rate the diving slightly better - certainly more diverse. A lot of south Bonaire looks pretty much the same after several days. There's nothing like Mushroom Forest on Bonaire either although IMO it's highly over-rated - so much coral structure the fish have no where to hide so are sparse.
What are the kids going to do on Bonaire when non-diving? Watch the kitesurfers? The Donkey farm is good once. There's a wider variety of kid-friendly activities on Curacao.
You could make Cayman work also without the diving from the resort aspect. All of Seven Mile Beach is pretty nice. The Marriott/Westin have Red Sail on-site - they'll shuttle you by van to their boat or pick you up off the beach with one. No shore diving on SMB - too flat and shallow. As mentioned, SH doesn't have any beach but would be good for an afternoon dive. Except both the Mermaid and the Nicholson are too deep for her so that might be disappointing. Rent tanks at Eden Rock or Divers Supply and dive Smith's Cove - it's shallow a long way out. Eden Rock is also mostly above 40' but generations of cruise ships mooring in front of it haven't helped - it's pretty ground down.
Another option within your daughters range are some of the NW side shore dives. Turtle Reef is arguably the best for access, nice stairs to a protected cove then a short swim out to the mini-wall. One direction it bottoms out at 50' - north closer to 70'. But the wall starts around 20' and is covered in stuff. Plus it's namesake usually is swimming around. At Lighthouse Point there's an old anchor real shallow - and Cobalt Coast is shallower also. Both have dive docks to get you over the ironshore and Divetech on-site. Info on all these sites and several hundred more can be found at
http://www.dive365cayman.com/
Downsides - Cayman is very expensive. For a family, boat dives are going to be 2/$100 everywhere. Some of the operators go with very limited loads though - off-season it's possible you'd get your own boat if there's enough of you (6-8 max is the rule for many) I doubt that applies over Christmas.
The downside for boat diving is that everybody goes there to dive the deep wall so most 1st dives may go to 100'. And some moorings are closer to 60' so it's blue water diving for your kid - not much to see/interact with. Second dives would be shallower and some operators like Red Sail also do a shallow afternoon dive - they do certs/discover dives so it won't much exceed 40'. And there's also Stingray City - it's 15' deep. A lot of fun - once.
hth,
