The difference between the reef trip and flats trip is all a matter of your preference. I did both ( but I'm a fishing nut

)The flats trip would be somewhat crowded if all 4 of you wanted to fish at the same time. Almost impossible I would think.Fishing for bonefish is 99.9% sight fishing.Most often done with flyrods, but can be done with Spinning gear as well. you can troll the flats with live bait and most often than not pick up barracuda.
For the numbers of fish and the variety of fish I would def. recommend a Reef trip. This can either be bottom fishing or trolling. Either way should pick up quite a number of fish off the reef.
I don't dive, but there are very very many on here who do and are very helpful when asked for reccomendations to dive guides.
You will find that Xanadu posts all sorts of trips fishing, caving, zip-lining etc. and as far as I saw they were comparable to every other place in town. If you contact Susan at the Office by Email and let her now what you are looking to do I know she will have it all set up for you when you arrive. However, no matter who you book with you will have a wonderful day of fishing ( weather permitted of course).There are so many guides available, and from reading peoples reports here the majority of them are excellent.