Active Jehovah's Witnesses have been warned away from cooperating with researchers. On the other hand, many are on facebook regardless of the society's platform warnings against that medium. Perhaps you would get more success by running an ad on Facebook?
If you are looking for good, baseline sociological data on the influence of religious upbringing, I have found www.barna.org to be very helpful. My gut tells me that JW and evangelical upbringing has many similarities.