It's been a few years since I went to Italy-( Last I remember they didn't even wave on the way in. So unless things have changed that rule on the number of rolls of film wasn't being enforced. It's likely aimed at people bringing in grey market film to resell not your average tourist bringing in a suitcase full of film to use. OTOH if you've got the time I'd consider getting the film there. With all the stuff at the airports I wonder what it does to the film. I'd try the European website [Italian and German] and ask if they will ship to your hotel. It will end up a little more expensive then the cheapest US prices but you won't have to carry the stuff over.
Tripod? How often are you going to be allowed to use one inside? Rome and Venice to me means large tourist sites. Lots of people. Lots of guards. No tripods. Outdoors during the day you should be able to handhold it.
Bags in tourist sites put you at risk of purse snachers. However it's spelled.
Also it's going to be warm that time of year. I'd also check if the places you really want to go to are open in August.