I ordered some button eggs on
eBay too. I candled them tonight. 13/15 are surely alive, One egg was my fault, I dropped it and it cracked slightly, but I assumed it would be okay and put it back in, the other I am not sure if it is still alive or not. So if all the alive ones survive ill have a 87% hatch rate, which I would be super happy with.
As long as the seller packages them right, there is nothing to worry about their safety, unless the box gets completely smashed. Mine came in a big foam cube with holes for each egg, and all of them arrived perfectly intact, with not even the slightest cracks, I candled them right when I got them so I didn't miss anything. Although one thing that may happen no matter if its the best packaging or not, is that the air cells can detach with rough treatment, which is out of anyone's control but the post office.
Not like I recomend this,

, but I had problems keeping my incubator warm enough on day 3, it was only 90 degrees for two days and 60 degrees for two hours, so I'm surprised almost all my embryos made it! But I think it may be due to the fact that my room is a cold 58 degrees ( i currently have no heating in my house and it is torture!!) so make sure to keep the incubator in a room with about 65 degrees, and keep the temp preferably at 100 degrees F, but it isn't a big deal if it drops or raises a degree, only for a limited period of time though.
I used a chicken egg turner but taped tissue paper in the cups so the quail eggs don't fail through. Humidity 40-55% (50-55% ideal)
I ordered from South Carolina
Sorry for the long rambling post and good luck hatching eggs!