You should still use reinforcement in the concrete:
Use basalt rebar instead of steel; it will not corrode.
Use a nylon fiber in the mix to protect against impact and spalling from fire.
Use 5000 psi concrete instead of 2500. This is much stronger and will be less likely to break down under any environment.
Use a vapor barrier underneath to help prevent moisture and gas from coming up into the house.
Put the foundation on 8 to 10 inches of 1" rock. This will help protect against soil expansion and allow water to quickly flow underneath or out of underneath the house. It will also prevent critters from digging into any possible underground utilities, etc.
Any cracks after the concrete sets, fill and then seal the entire pad.
Be sure to keep the concrete wet and covered for 30 days to aid in maximum strength.
Instead of a steel frame, use insulated concrete forms, again using basalt rebar. This makes a concrete walled house. Use stainless steel trusses (or onsite galvanized steel) for the roof or build a concrete roof with similar construction methods as the insulated concrete forms.
The siding of the house should be concrete board or other non combustible material (brick or stone)..or both where it makes sense. But be careful on the mortar used..seal it at least if you expose any of it to the weather.
Make sure the eaves are at least two feet out and the eaves over doors more than that. This keeps water away from those areas and the house as a whole.
Make sure you have gutters...good ones.
Make sure your land around the house moves water around it - even in flash flood events.
Have real shutters for your windows.
Where it makes sense, especially those areas exposed to weather, do not use wood.
Instead of slate..use aluminum shingles.
Forget the fireplace...too many potential issues with fire, leaking, etc. They are hard to build for 20 years let alone 1000.
Use Fiberglass windows. The best ones will outlast any hardwood.