I'm going there about the same time as you. Wunderground says average temperatures vary between 45 and 68 in Rome, Florence, Venice between Oct 19 and Nov 4, and average October rainfall is 3 inches. So I'm planning on a light down jacket for cool mornings and evenings, a nylon vest for daytime and transit, my usual Rockport suede shoes plus Birkenstock sandals for inside, a wool watch cap and a baseball cap. All subject to actual forecasts closer to departure. Hopefully the pre-departure forecast will tell me enough about rain potential to decide between my hooded Gore-tex parka, for expected rain, and a light plastic fold-up poncho, for insurance. This is based on general travel experience and the best info I can get now about weather to expect on this trip.
Layering is definitely the name of the game, anywhere and anytime. And if you're worried about wet shoes that won't dry out, bring extra socks.