Let me start off by saying that I like the idea of the PB's mounted on the perimeter beams and grazing the tongue and groove ceiling. You might get the fixtures in white and mount them as such that the longer part of the shroud faces downward so there'd be no visible light coming from them as you look from below. They could be mounted on the vertical part of the beam to accomplish this. The NL will make a good downlight for an area like this. You can really put as many as you'd like along the insides of the beams over the counters and grills. My suggestion would be to get at least the 3 LED unit of the downlights because with Luxor, you can dim them down less than 10% output, yet having the 3 LED set up, will allow him to brighten the place up nicely if needed.
Mind you, you can put some of the downlights on one group and others on another group. Your limited only by your imagination. ( and his budget)
Now to get to the meat of your questions. The LUXOR component not only adds control to the LED fixtures, but full range dimming as well. For this application as you've outlined it, the LUXOR system will let you call, for example, the uplights Group 1 and the downlights Group 2. Then with the programming and theme controls, you can set up the unit to turn the lights on automatically and at what percent of brightness.
As far as him being able to use the system with his existing pool controller, that might be an issue. The LUXOR system is stand alone and wouldn't need to be interfaced with a JANDY type controller because it wouldn't work.
Rather, and as discussed previously on this thread, the Luxor system will be updated and more bells and whistles will come out for it. I'm hoping that they incorporate wifi and have smart phone capability. IN that scenario, the client would, upon getting ready to cook at night, whip out his iPhone, and dial in his lighting and turn his downlights up to 80% to see what he's doing.
IN the meantime, my suggestion might be to locate the LUXOR unit in such a place that the client has access to it and can change the lighting just as if they were dimmers on each 'zone'.
The Luxor control panel connects with a short RJ11 cord such that if you got a longer RJ11, you could set the controller up at a location that was not where the transformer is.
As much as you could accomplish what you are trying to do with incandescent lights, zane dimmers, a regular transformer, and integration with his pool control, it won't be the same.
The LUXOR system doesn't dim incandescent or halogen.
I'm guessing there is a cabana around this cooking area? Good location to put the Luxor unit? With the FX ZD fixtures, you can now( or later) add more lighting for the landscaping, pathways, security, etc. and integrate them into the Luxor system simply by programming them to another group. In the long run, this system will give your client the most flexibilty, actually save on core cost because you only need one transformer ( per 300 watt lighting load), and will allow him to have full range dimming to set the mood just right for when he's entertaining.
Hope this helped..