Sounds like an awesome trip.
For Athens, you may want to consider a food tour. We have taken our teenagers on them in the past and it was one of the highlights of the trip. For Athens, it was just my husband and I, we loved our tour with Eating Europe Greek Food Tour. A great way to find the hidden gems in the neighborhood that you are staying in. No recommendations for Acropolis view restaurant, we actually took a cooking class and ate our meal that we cooked on a patio overlooking the Acropolis.
For Myknonos, on the Friday if you are not going to the clubs, then I would recommend 180 degree bar Myknonos. It is pricey, but an amazing view, good food and drinks. Also typically has a live band. Very fun and young vibe, great pictures.
I would also second recommendation to visit Delos. It is a short boat ride from Mykonos and is one of Greece's most important mythological and archaeological sites. It is the birthplace of Apollo and Artemis, and was the major religious, political, and commercial center in the 1st millennium BC.
Santorini, especially in Oia and Fira can be very crowded if cruise ships are in town. So as you look at your itinerary, you may want to make some modifications to your schedule to avoid the worse of the crowds if you can, for example, if there are more cruise ships on Sunday, you may want to switch or Monday and Sunday activities.
On Tuesday, you may want to reserve your Santos winery visit until Sunset as they have amazing views from the winery. If you need something in between to leverage your time, you may want to visit Pyrgos. It is a traditional village known as the island's highest point, offering panoramic 360-degree views from the slopes of Mount Profitis Ilias. There a well-preserved Venetian Kasteli (castle), over 40 churches, and a labyrinth of narrow, whitewashed alleys. Franco's cafe's view is amazing, great coffee also. We went on a day when there were 3 cruise ships in town and there were maybe 40 people in the entire village. After visiting Pyrgos it is a short, but a bit dangerous (cause of traffic) walk to Santos Winery.