A week from tomorrow, I'm taking photos for our parents of multiples group (twins, triplets, etc...) while the kids visit our Santa. I'm aware that I need to watch out for glare with his glasses but are there any editing problems I can avoid now with good preparation? I know the color red has the tendency to give cameras a hard time. I believe they're supplying a white background. Any advice is appreciated. My setup is a simple canon flash on a single light stand bouncing into a 43" silver umbrella in case that assists with the advice.