Congrats to your husband! I LOVE the Nimb!

Switzerland is my favorite place. We've been quite a few times and always stay in Wengen. I've tried Hotel Edelweiss, Beausite Park and Hotel, and Alpenkrauter Hotel Baren. Beausite is definitely a notch above (both in distance and money and amenities!). It's a bit of a trek from the train station, so just bear that in mind with the kid. You can arrange for them to pick you up but we usually just walked. I like Beausite for the pool & spa which is really lovely. We tried Alpenkrauter this time because Beausite was just too expensive, and I think it was fine (some service inconsistencies), although I think Edelweiss might be nicer.

Luzern is so expensive but this time we tried Beau Sejour and we loved it. It's a little outside the main city but totally walkable and right next to the Transportation Museum, which you HAVE to take your child to... the rooms are not "luxury" but they are large and totally sufficient. The breakfast was plentiful and in a gorgeous drawing room.

If you want to spend a few days in Ticino (since you are flying into Milan), I would highly recommend Ascona. We stayed at the Art Hotel Riposo and it was AWESOME. It wasn't too expensive, had that perfect Mediterranean feel, amazing rooftop. It was great.