If I read it correctly, you're planning to spray the attic floor with high-density foam, but ventilate the attic space with soffit+ ridge venting(?). With ANY spray foam (even open-cell low-density stuff) the vapor retarding quality is sufficient to make the attic venting superfluous if it's a no-access space. But if you have access ports & electrical/mechanical penetrations to the attic or if it's being used for ducts/vents/storage, etc. you're better off spraying the rafters and NOT venting the attic, making it all conditioned-space. It would mean a higher volume of foam, but would have fewer problems worrying about leakage point losses into the attic space from the living spaces.
Most high density closed cell foams use CFCs- they're higher R-value per inch than low density water-based low-density foams, but the low density stuff has fewer shrinkage issues, and is cheaper per R-value (though it has to be thicker) than the higher density stuff. There are some intermediate-density closed cell foams out there that are water-based though- shop around, see what's the best (and greenest) value for your application.
The high-density stuff may be called for in a retrofit situation where the available depth is limited, say a 2 x 4 framing wall, where you could get R24-25 with high density, but only R13-14 with the low-density foams. In attics there is generally enough space to make the R-value whatever you like.
On a separate note, compact fluorescents aren't necessarily the best option for ambient lighting. A typical CFL puts out 50-60 lumens per watt compared to ~90 lumens per watt for T8 (1" diameter) linear fluorescents, or 100+ lumens per watt for T5 (5/8" diameter)linear fluorescents. If you install up-lighting coves or cabinet-top fixtures using walls & ceilings as your reflectors/diffusers you can get a lot better lighting quality (no glare) and run at lower overall power for a given ambient light level. There are dimmable ballasts available for both T8s & T5s- they require compatible dimmers, and some require special wiring, but there are 2-wire versions too for not a lot extra. If you're using recessed downlighting, there are dimmable fluorescent versions of these too. But too often recessed downlighting adds glare which interferes with vision- better to do the heavy lifting of ambient lighting with uplighting- bright ceilings & walls just plain FEEL better. But as importantly, humans can see better without the glare, even at dramatically lower light levels. (Glare causes your pupils to constrict more, so you end up needing more light.)
Leave the standard compact fluorescents for table lamps, etc. (And consider using 2 to 8 watt cold-cathode CFLs instead of the higher wattage standard CFLs- they're nice for mood lighting, dining etc, if a bit on the dim side for providing the whole room ambient light. Cold cathode lights typically last 2-3x as long a standard CFLs too, with no heater-filaments to burn out.)
dana