Has anyone here been to Italy in February? Do the Vatican’s Basilica and other landmarks and museums close during Carnivale?
Nothing closes for Carnevale, certainly not St. Peter’s Basilica.
But for specific museum hours you need to consult the individual museum websites. Some close on certain days of the week, for example the Vatican Museums close on Sundays. If there are special events they might also close, for example when the Pope dies, and the Conclave takes place in the Sistine Chapel, the Vatican Museums are closed. As of today Pope Leo looks like is in good shape. He carried the cross all day today as part of the Easter events.