Good question. With infrared obviously being a light, in this case and the amount of light we are talking about I am going to go out on a limb and say in this instance it wont hurt anything. I have a few cameras as well laying around and been thinking about putting a couple in my grow room to, just have not got around to it yet.
Nah, don't sweat it. Look at a PAR curve, it falls off tremendously after 750nm.
I haven't seen a curve that went much pass 850nm. So near and far IR is an unknown, but looks 'invisible'.