If you create Families with Rhino.Inside.Revit then the resulting objects are Forms. The surfaces of those can be edited in Revit actually in a limited way. There will be no active parameters.
This workflow is covered in this tutorial: Loadable Families with Rhino.Inside.Revit
If the family is supposed to be parametric to be controlled through parameters, then the family must be made in Revit, but Grasshopper can be used to control the parameters on an instance by instance or Type basis.