Rebar, for sure. They have rust-proof fiberglass rebar available at Honsador now called "Gatorbar." If you want to go high tech on the cement mix, you can see if anybody offers metakaolin for the concrete, probably not. I shipped in a pallet of it from LA for my projects. Otherwise just get something with some fly ash and a 4000psi mix. Make sure the crew vibrates the pour.
Consider metal framing for the house.
Consider metal framing for the house.