If the junta is like a lot of prior juntas think they know best and form a coup.

a) What is the EUs policy? Do they have one?

Basic Business 101 is you build your exit clause at the start even more so if you are forming a partnership.

b). Considering the mixed success of Libya does the EU even have the capacity to effectively stop a coup in Greece?

C). If left to their own devices is the EU prepared for Greece realigning itself with another sphere of powers or worse becomming to the EU what Chechnya is to Russia? After all if a murdering junta came to power in my country because of the policies and then lack of action by outside powers I would expect to see a rise in terrorists going into the nations responsible.