Is is possible to apply ED 2 , and hear back from the college in early-mid feb (rejection) and then switch my regular application to another school to ED 2 if the deadline to do so is march?
If you were denied by your first ED2 school, then beyond mid-February you would be free of any potential commitments to that college. Therefore, yes, you would be free to switch your RD application to ED2 at the second school under the scenario you posted.