Hey,
I can completely understand your freakout. I love the ideas with candles, it will be so beautiful and romantic. I am not sure about the bonfires, I feel like you will need to post someone in case they get out of control, and the smell wont be pleasant. May I reccommend calling professional photographers. It costs no money to meet with them, and when you do, ask them or email them questions about candles. No one said you had to sign a contract. Ask what they do to prevent glare, and then just relay that to your friends and family members with cameras. Good luck!