Yes eggs should generally be kept quite humid, and we dampen our vermiculite before placing the eggs in the incubation boxes. You can incubate leo eggs between high 70s and high 80s, so depending on your room temp they should be ok. Reptile eggs can usually withstand some change in temperature and conditions, but you should never assume an egg is infertile until it is moldy and bad - I always keep eggs until this stage, as we have thought an egg was infertile before that has then turned out to be fertile later in incubation. Our leo breedings were unsucessful this year, even though we had a few fertile eggs but they didn't hatch and the baby died in the egg for whatever reason - I suspect it had something to do with being our females' first year of breeding.
I would advise you to house your male and female separately - otherwise your female could be so stressed and exhausted from being bred too much and your male could end up quite poorly, as males tend to lose their appetite while breeding. It sounds like you had a good breeding response anyway, but housing males and females separate and placing them together for breeding can get a better response.
