Your thoughts about Northern Italy

Ferrara, Cremona, Mantova are less known but each has a long history, art to match and a distinctive cuisine. Just remember that northern Italy - basically everywhere in the flat Po valley, but also Florence, is very hot from late May (now) to early September.

Consider Brescia and nearby Lake Iseo, or Trento and the northern Lake Garda towns. If you like architecture you may consider Vicenza which is not far from Verona. Bergamo, between Milano and Brescia, is also beautiful.

Ravenna for a day.

All above is fine, but I would reconsider lake Como. Como is great for kids and people who want to behave like kids (no implied criticisms of that) But I have found the other lakes to be far nicer. In particular take a good look around Lago de Como and Lago d'Iseo.
All the areas you mentioned are knee deep in museums and architecture. All of them are older than anything.
Consider the ages of the travelers, some of the lake towns are very steep in every direction, e.g. Bellagio.

Second Brescia - great Roman ruins, really interesting sprawling museum including in situ Roman ruins in the basement, interconnected piazzas and a castle on top of the hill.

Verona is a great walking town - the center is nearly traffic free and buildings with faded murals and painted details lurk in unlikely corners. There are cafes with outdoor seating everywhere in Verona whenever you decide to want to sit and/or spritz. I have a very low interest in opera but I would look into seeing an opera in an actual Roman arena just for the experience.
The an intact Roman Arena and Theater which are still used for events with music and opera being a big part of the city's summer schedule including concerts and opera. The Theater includes the Archeological Museum which is small but also gives you access to the rambling remains of old religious sites there. If you like modern art check out the small Palazzo Maffei Casa Museo which mixes ancient and modern art, a palazzo and rooftop tour all into one place overlooking piazza Erbe and is underadvertised. I think Piazza Erbe (looking past the market stands) is one of the prettiest piazzas in Italy. Verona has the 'elegant decay' feeling with faded murals on medieval buildings that the Veneto does so well.

As suggested you might look into Lake Garda versus Como given its proximity to the areas you're already visiting. Logistics to the upper side of the lake are more difficult since there aren't trains but buses from Brescia for the west side or Verona from the east side.

If you're fashion fans don't miss the Armani Silos in Milan - a custom built museum that allows you wander in and around the displayed fashions.

Have a great trip,
=Tod

Varenna and Bellagio on lake Como, are the most popular villages on the lake so potentially crowded, but it shouldn't be too bad in October, except for maybe on weekends

Florence will be crowded near the famous sights, pretty much from April to October

Venice, same as Florence, maybe even worse since it's smaller

Verona is crowded near the Arena and Piazza delle Erbe, and also near the (fake) Romeo and Juliet's balcony, but what can you do? We have to learn to share the beauties of the world with others.

Milan is crowded near the Duomo, but it's a large piazza, so you'll be ok..

One more thing I'll mention is that the season on Lake Como generally ends earlier in October than it does on Lake Garda. I would check the ferry schedule for winter reduced schedules for any lake at which you are considering staying in October.

=Tod

since you start your question "Dear Sirs", maybe you think you're chatting with the company reps - you're not. We are just fellow travellers like you.

And some (probably the majority) are more female.

Mark, if your request is for us to suggest less crowded places in the cities you’ve listed, you would want to go off-season. Those are the most crowded cities in northern Italy. I like all of the cities Lachera mentioned, plus Torino. Torino is a wonderful city that’s still off most of the top tourist cities…for now.