I am going to place a slab next week within my first course of block. My question is with coming winter and the slab being exposed should I use an air entrained concrete? I usually use non-air to get a better finish but am worried about the weather. I am in central NC so it is not horribly cold for long spells but there will be temperatures in the teens for a few days at a time. Any thoughts are greatly appreciated.

air entrainment is used to mitigate the freeze-thaw cycles of cured concrete in exterior environments when it gets wet.

AE isn't necessary for interior slabs, however, it is winter, and I'm not aware of AE affecting future floor finishes. I assume you would be exposed for maybe 2 weeks, so I would probably not bother with AE. The first week is the time you need to watch and protect your slab.

Even slabs that are poured and then freeze, do reach good strengths according to ACI tests.

I would use insulated blankets for a minimum of 4 days after the pour. Normally you can rent them.