More mental Italy plans

Ok, so with limited time, I am making more plans, picking the must sees. These are the For Sures. With only about 2 days for each...choices are limited

Venice,
GOOD mask shop
St. Mark's
Thinking about the Jewish History Museum
Lots of atmosphere

Florence,
Uffizi
Academia
ponte vecchio

Rome,
Pantheon
Sistine Chapel
Colessum (on a friend's request)
Trevi Fountain

Any other suggestions on any of these cities? It will be November, so a bit cooler. I am an art lover, my friend is more into history. Thoughts?