I'm in a dry climate and have no trouble storing hatching eggs on my kitchen counter. My house temps range from 70 daytime to low 60's at night right now. The eggs do fine.
It could, depending on what the EE carries. Since EE's are mixes, you can never be sure what they carry until you breed them. If he carries the blue egg gene, then some of the offspring would lay olive eggs when crossed with a Marans. You'd likely get some that lay brown too, as the EE is likely not pure for the blue egg gene.