>>but please tell me if I'm doing something wrong with the eggs?
Joann, I don't pretend to be an expert, but if you think those blackened eggs were moldy, then you might look for a way to AVOID misting. We find that dry & well-ventilated is good for rearing. Having things too moist can invite problems. Sometimes I can put leaf petioles between moist paper towels, and that keeps them going long enough for the larvae to hatch. Sometimes I stick the leaves in water, again, just the petioles, in tiny vases or mini water bottles with nail-pierced caps. Best of all is to clip part of the plant, if you can, so that it stays fresh and pliable without having to mist. Then, when eggs hatch, the little fellas are well-supplied.
Not a monarch doctor; don't play one on TV! But I'd avoid the mister if possible.