As long as you enjoy trying..you have another shipment coming from me. You are up against some odds though. How do I put this politely....I have no faith at all in those incubators. If you are sure that you have really good thermometers that you can trust, that's a great thing. Humidity, you seem to be on top of it. The turning ...? Not so sure about those little bators.
And.... you are trying to hatch one of the most difficult of chickens- from shipped eggs. I know other breeders who won't ship Serama eggs because of this. I will, but I usually end up shipping a second batch to give better odds. Sometimes, someone will surprise me and hatch about half the eggs. It took me awhile to build my Serama flock, hatching one or two, sometimes none from shipped eggs.
If you don't care much for hatching eggs, and all you want is a buddy for your little girl, you might consider having one shipped to you. If you really want to hatch your own, keep on trying, it will happen. Only you can justify the expense of another incubator and how much use you would get out of it. I guess you could always resell it if you get something like a Brinsea. Even a styro-bator would be better. We understand those well.
So don't kick yourself, at all. and get out there and do something for Halloween! We'll work on a Thanksgiving chick....or a Christmas chick....