I had to look up Barbados Cherry! It appears both these plants will grow into large trees but I presume you know what size they will be for you.

Both are also tropical plants needing direct sun. Your setup will provide, at best, a little under 2,000 foot-candles. This would probably be just about sufficient for short plants since you can run the lights full on maybe 16 hours a day, but a tall plant (2-3 feet, I'm guessing?) will need more, especially if you are looking to fruit them. Also, I think the leaves will scorch at 6" from your CFL bulbs.

I would suggest another couple of the bulbs and try to arrange them so that they are as far from the foliage as possible. This will help to illuminate the bottom of the plant nearly as much as the top which is important for growing tall plants under lights. Perhaps you could arrange the bulbs in the corners of your boxes, or maybe even a couple of them partway down the sides.