hydrofoil? where are you going to and from?

Maybe from Milazzo to Lipari.

I finally got an answer from L'Approdo delle Sirene stating that "Don’t worry about the ZTL because at your arrival we will send your car plate number to locale police, so you will have full access to the ZTL." - which is great news. They also promised information about "special events" - if any during that weekend, as we get closer to our departure date. I will try to call on Monday some of the listed Tourist Offices to try to find out what's open or closed on those 3 days in Siracusa, Ortygia, Ragusa Ibla and Noto out of what we would like to visit/see.

I'm so glad you finally got an answer from L'Approdo delle Sirene!

IMO, Lipari is well worth a bit of time if it appeals.

I do not dare to get tickets in advance for Lipari as it could be only a 1 day visit and I am concerned about getting stranded there due to the weather. So we will see probably when there.