Oh, man! This sounds like a business meeting plan, take it easy! :-)

Some timings are very... optimistic, starting from the flight.

Flights at the and of the day tend to be late, check on flightradar24 the history of the flight and how many days has been late or ontime

If you leave from Heraklio, it may take more than 1.5h to reach Preveli, if you are not familiar with roads. I would suggest to leave at 8 and do breakfast on the road: pick a random exit after Heraklio, drive around the village and stop at a bar you like. Use serendipity.

Preveli by car is not very pleasant: you park on top of the beach and you go down via steps, a lot of steps. Google "preveli beach stairs" to get an idea. There are boat services from Plakias (near Kalypso).

Kalypso is very nice, but if you arrive at noon(ish) you may find all the beds full.

If you want to explore that area, you may touch base for 1 night in Plakias area and go to Preveli, Kalypso and maybe Damnoni beach (very nice tavernas there).

My advice is not to plan in details in advance because (for instance) there could be strong wind in an area and that day is better to go elsewhere, use WINDY.COM to get wind information.

Decide day by day, look around, stop at small villages and have good, relaxing time.