>  am concerned about getting through customs and getting to and from the airport to the hotel. Will i have issues in customs, or are there english speaking staff available?

Living in Greece all my life I can assure you that, nope, you won't. 

As a famous tourist destination almost all tourist related jobs here require some sort of proficiency in speaking English. In places like customs I believe you'd be hard pressed to find someone who *doesn't speak* English. 

Taxis might be more of a mixed bag but the metro is always an available and less expensive option with employees that are, again, required to be able to speak english.

Finally, you can always ask around if you need anything, the younger the person, the more likely they speak English. 

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Note, of course, all this applies to Athens. The further you get from any city the less likely you are to encounter people who will understand English.