Yes,they really do limit you to 1 large suitcase each and 1 carryon each. The large suitcase,up tp 30 in., can have wheels. The carryon cannot have wheels and must be small. Globus will send you a small case to use as your carryon. You can use it or use your own.
Use the ATMs to get cash and take a credit card for purchases.It's easy. Be sure you have a 4 digit pin number and that your money is in your checking account. You cannot access a savings account from the Atms in Europe. Don't worry about finding an Atm,they are everywhere. Be sure to notify your credit card company and bank the dates that you will be traveling so they don't put a stop on your accounts when they see foreign transactions coming through.
Get an under your clothes waist pack or neck pouch and carry your passport,tickets,cash,Atm and credit card in it.
I bring a comfortable pair of walking shoes and sandals. You will do lots of walking on cobblestone streets.These tours are very casual so slacks,jeans,capris,skirts are all good.Do not bring halter tops or shorts. They are not apppropriate and you won't be able to see the inside of the churches. Even tank tops are not accepted in the churches and if you wear them carry a scarf to cover your shoulders and arms when needed. If you are not going into a church tank tops are ok but never shorts.The tours are very casual so leave the dress up clothes at home. There was only one night where people dressed up a little and that was the farewell dinner. None of the guys wore a tie or suit and the women tended to wear a pair of slacks with a dressy top just for that one night. Many times people wore for dinner what they had worn touring the day.It will be very hot in Italy in August so bring clothes for hot weather. Also bring an umbrella just in case.
You will not have much free time but all of the Europeon cities I have been in have a very good public transportation system.Just watch out for pickpockets just as you would in anyy large US city. Europe is fairly safe and has very little violent crime. You are safer there than in a big city in the US. The only thing you have to watch is thieves.Just be aware of your surroundings if you are out late at night. I am a single woman and my girl friend and I walk all over and have never had a problem.
Globus hotels are fine although sometimes not right in the center of town so you might have to take public transportation if you wish to get to the city centres on your own.
I have no idea if your kids will like it,I don't know them. I have been on other tours where there was kids and they seemed to be having a good time. The parents would in the evening try to find things to do that their kids would enjoy,like ghost walks etc. I am sure they will be fine and surely they will appreciate such a wonderful opportunity to go to a foreign country.. . As long as they can read and listen to their music on the coach they should be fine. If you have girls tell your daughters to be aware of Italian men. They are known to be very charming and full of it.

They are also much bolder then American men.
Use the search function on here to find information regarding your particular tour. Many people have taken it and posted trip reports. Even if it is not exactly the sane tour all the tours in Italy seem to have the same optionals.
For information on hotels and restaurants I use the tripadvisor web site. Go to the Italy forum and you will get lots of information.