It seems to me that religious belief and religious practice should be distinguished. The current questions are about religious belief and family background. Perhaps a question like this:

How many times in the past year have you done the following practices? Estimates are OK. The question here is whether you did the thing, not whether you believed in it, made it a habit, or did it voluntarily.

• Attended a religious service?
• Attended a "regular" religious service (e.g. a weekly church or synagogue service, Muslim daily prayers, etc.; not a wedding, funeral, or holiday service)?
• Prayed to God, gods, saints, or other religious figures outside of a religious service?
• Done yoga, qigong, or another movement practice derived from religious or spiritual beliefs?
• Used or participated in psychic or fortune-telling practices (palmistry, ouija, I Ching, tarot)?
• Meditated?
• Meditated for thirty minutes or more in a single session?