The tile will be fine. It was fired in a kiln at high temp and if there was anything on it, it's gone. That is what they suggest you use so that you can take it out of the tank and put it in another tank the night they are going to hatch. Unlike mine, that lay them on the LR roght next to the GBTA and I can't take it out of the tank. I'm working on trying to get them to lay on pots that I have put in there. We will see how that goes.
As for them breeding, get yourself a timer if you don't have one. There is a great writeup on here on exactly everythign that you need to do in order to breed. The lights have to come on and go off at the same time every day and something as little as moving something outside of the tank can get them to not spawn. Or, they can be like mine, a couple of jack rabbits that won't quit. Mine lay about every 16 days at the most.