On a single story house, can anyone provide the cost per square foot for these exterior wall options ? 2x4 16"oc. stud wall with 4" of polyiso foam on the exterior. ICF, 6"concrete Double 2x4 wall 10" thick with high density cellulose.

It really depends on your local labor skill base and labor rates. If you have a builder who is up to speed with one of those, that option will be cheapest.

That said, ICF is likely the most expensive of those options, assuming you want similar R-value, and maybe even with lower R-value.

And look into reclaimed foam. If you do that, you can cut the cost drastically for the first option.