Iten. help in Switzerland - Basel region or Lausanne Region?

Hello,
Definitely Lausanne / Vevey / Montreux over Basel, the lake Leman région is beautiful. You can then take the Golden Pass scenic railway from Montreux to Interlaken for Wengen.
Alternatively, Luzern and surroundings is worth seeing too.

4 nights in Zermatt is a lot however, unless you plan many hikes. Could you take one night out?

After Zermatt my recommendation would be... Lake Maggiore in neighboring Italy. Stresa, Baveno, Verbania make good bases and are easy to reach from Zermatt.

After that it is easy and cheap to fly from Milan (Malpensa) to Paris. Or, if you haven't booked yet, maybe you can fly open jaw: into Paris, out of Milan. But I assume you've booked since you mention Paris.

1) Zermatt is all about relaxing and hiking so we will be doing hikes everyday while in Zermatt and open to a day trip from there too if time permits. :)
2) I've been to Italy - Lake como area already so still debating if to do Italy or just head to Paris after Zermatt and relax there for 2.5 days before our flight to the US which is already booked.

The question that jumps out at me is: You do not appear to be spending any time in Paris. If that is the case, why are you flying into and out of Paris?
it would be more logical to me to fly into Zürich, and, if as Balso suggests you end up in the Italian lakes, fly home direct from Milan.

Also, it is not a good idea to take a long train trip (Paris to Switzerland). You cannot predict when you will emerge from the airport, so you cannot buy cheap advance tickets, and buy-on-the-day tickets for French TGV's are very expensive.

• I would suggest head direct to Wengen (from Paris or Zürich airport).
• Slot one of Lausanne / Vevey / Montreux in between Wengen and Zermatt.
• Then Zermatt.
• Then follow Balso's plan, down to Stresa or somewhere else on Lake Maggiore.
• Then a short run to Milan Malpensa airport.

BTW, what time of year is this? That might affect things.

Im going next month - it was significantly cheaper to fly into paris :) i might spend last three days in paris im fine with that too. flying into zurich was 2x.

We spent a week in Lausanne last autumn and enjoyed it very much. However, the next time we would stay in Vevey as it is smaller, with a more charming lakeside. There are some nice mountain excursions from there: Les Pléiades and Rochers de Naye.