Hey and welcome veroj86:-) Well, you don't have 2.5 hours to be exact.. you have 2 hours and 15 min;-) Every minute counts when dealing with entry formalities/luggage retrieval;-) Having said that, I agree it's a good time spread if your inbound flight from Croatia is timely:-)
Athens airport is super user-friendly, modern.. easy to navitage.. all under 1 roof or terminal building so after formalities at arrivals, you simply go up one flight to check in for your domestic puddle jumper;-) You can take a look at the official site at www.aia.gr/
I've never flown Cyprus Air but have on Aegean.. great carrier IMO;-) FWIW, this is bottom line, a personal call.. your comfort zone rules;-) I don't think you'll have a problem with the time spread in making the Cyprus Air flight.. but no one can guarantee that the flight from Croatia won't be delayed.. to be one the safe side, you can always go for the Aegean flight and plan on having dinner at the airport.. or at the Sofitel right across the Street that has a 24X7 cafe.snack bar as well as a full service restaurant?;-) Again, it's your call, your vaca.. your travel style;-) You're coming the distance, how much of an inconvenience would it cause you if there was an incoming delay that causes a miss?;-) Although chances are good you'll make it.. there's always a 'chance'.. 4 hours and 45 min doesn't sound that bad at this point, does it, lol?;-) Happy planning.. and enJOY!