You will have a wonderful time in Sicily! here are a few suggestions:
Palermo: CiCala wine bar is a lovely, friendly place to try Sicilian wines, and the food is excellent as well. Great small plates and delicious pizza.
For excellent seafood, Osteria Mercede is wonderful, but reservations are a must.
Opera de Pupi! -- the style in Palermo is different than the style in Ortigia, and we recommend going to a show in both locations
Cefalu: we are in the minority, I think, for not *loving* Cefalu, so 1 night sounds about right. the walk along the seafront is lovely, and the Duomo is quite striking, especially the new modern stained glass windows. the walk along the roof is great. we had a really nice dinner at Locanda di Marinaio which was not our first or second choice but those places were closed on the night we were there. pricey, but inventive, delicious food and the service was spot on.
Taormina: again, we're in the minority for loving Taormina despite the crowds and touristy stuff. the gardens are gorgeous and the views all around are spectacular. get out early to walk around, and enjoy evening walks through town as well. the most memorable we had here, over 6 nights on two separate trips, was a private cooking class dinner at Villa Brittania. Rosmarino was also good, and for pizza, salad and wine Villa Zuccaro is our favorite
Syracuse/Ortigia: lots of choices. morning coffee at Crema e Cioccolato on Via Giudecca was our favorite, hands down. better than the places near the Duomo and cheaper, too. Our best dinner in Sicily was at Cortile Spirito Santo -- rather expensive but everything was fabulous and interesting and delicious. nice option of you're in the mood for a splurge. we also had a great leisurely lunch at Dave Sicilian Taste also on via Giudecca, in a lovely small square. Best gelato: Gusto
Have so much fun!