Neither of the first two have liveaboard options currently although MV Pearl may be working in Utila at some time in the near future. It's the former Utila Aggressor but the exact status seems to be unclear since they changed to Dive Encounters Alliance.
Honduras Bay Islands Live-Aboard Diving | DivEncounters Alliance Live-Aboard Diving
Bonaire is about the best shore diving. Most of the waterfront resorts are dive resorts. Most people you meet are divers. Except for the cruise traffic downtown there isn't a lot of draw there for non-divers. At many of the dive resorts, Buddy Dive, Habitat, Divi Flamingo, Carib Inn, Eden Beach, - just about everyone you meet will be a diver. Most people buy a shore dive package - they run under $200/wk. That includes a 4 dr. pickup truck. So there's almost always room for one more. And there's also boat diving and shore diving off your resort - or the 4-5 others adjacent to it. Downside for you is most have higher single occupancy rate - maybe not Carib Inn, I think he charges by the room. But it's a smaller place so less likely to find other singles there.
I was asked twice if I needed a buddy while waiting for mine - once at Habitat and once at Bonaire Dive & Adventure's dock. You can also post both here and on bonairetalk.com looking for buddies who will be there when you will. You can also buy all manner of boat dive packages - most include unlimited shore diving also. For us 4-6 boat dives covers the highlights of sites you can't reach from shore.
www.infobonaire.com has info on everything. bonairepros.com specializes in booking Bonaire also.
Maybe look at Curacao also. It's more spread out and less dive-focused. But there's Lion's Dive Resort, nice place. The Sunscape AI next door has a dive shop on-site but seemed more kid focused. A couple others in the West (much quieter) end of the island. I don't think you'd find the concentration of single divers you seem to want out there. One other option for shore diving is the Dive Bus - they pick you up for escorted shore dives all over Curacao.
On Roatan try one of the AI dive resorts. Cocoview, Anthony's Key or Reef House. Probably everyone there will be a diver. You'll meet the people on your boat since they'll be the same all week. And eat all your meals with them and everyone else. There's not much else near CCV or RH.
All the nightlife on Roatan is focused in the West End - about a 5min. cab ride away from Anthony's Key - 45mins. from Cocoview. There's many bars, shops, restaurants in about a 1 mile stretch. Cocoview sometimes runs excursions over there also. Except for the dive(s) off Cocoview, there's really no good shore diving on Roatan. AKR advertises one but I've seen it, it's not great. Elsewhere shore dives are few and far between.
Another option might be one of the singledivers.com trips. You might also contact someone at caradonna.com - they book a lot of dive travel. And if you can go earlier, there's the Scubaboard Invade Bonaire trip in July.
http://www.scubaboard.com/forums/invade-bonaire-2013/
IDK anything about Panama.
