ATM at every resort hotel I saw, and the touristy marina / restaurants area in Hurghada (which I cant recall the name of, sorry).
Cabs:
Dont get in a car that isnt marked as an official cab (I think they were green?)
There are standard rates for various locations. Ask your hotel or liveaboard what it should be.
At end of trip give cab that much (tip if you like). Get out. Do not get into conversation about price. Hold your ground if they try to.
They also like to play games where they palm a note and say, no you only game me x, you didn't give me y.
To be clear not every cabby does this, but enough do that you treat all the same. Get out hand money, keep walking.
Keep in mind what the exchange rate is. I recall a cabbie shaking me down for 20 pounds, we are only talking about roughly a dollar. In principle it bothered me and I responded like someone who doesn't let people shake him down, but in retrospect wasnt worth 5 minutes of a vacation with a shouting match with some stranger.