Does the EPS provide support for a wood sill plate?

No, the EPS has no structural capacity to support any loads. Wood sill plates must achieve the required bearing from the concrete within the ICF. A wood plate that cantilevers 1 /3 over the EPS and bears 2 /3 on the concrete is allowable. This can be done with a minimum 2 x 6 plate. If a 2 x 4 plate is required, a taper top form should be used to extend the concrete under the plate.