Dear Andrea,
buongiorno! I am sure that there will be the chance to find the best suitable van for you and your friends/family. I would surely recommend BLUCARSERVICE, they both have 7seat vans or 8seat vans. Matteo & Mauro run the company in a very professional way, they can customize the trip to Chianti according to your needs and suggest lots of "cantine" (cellars). As far as Florence you may decide to tour the town both with a tour guide and by van. It will be extremly comfortable, easy and quick. You may inquiry directly to BLUCARSERVICE, they are also in touch with selected tour guides of Florence (info@florenceguide.net).
By van in Florence you may tour both the hills (Fiesole or Piazzale Michelangelo & San Miniato church) and the city center, which is accessible to authorized vans, as far as the Oltrarno district. Short walks + enjoyable local experiences and transportation throughout the day.
Wishing you a nice stay in Tuscany
a presto
Elena