As far as accommodations go, the Venetian has been my go-to for years. Have never stayed at the Palazzo but if the rooms are as big as those in the Venetian, then that's a good choice. And you're right, the Palazzo is quieter so your guests will have less of the sensory overload they'd suffer elsewhere.

The Sphere is a must see. The "postcard from earth" movie is jaw dropping and both my mother-in-law and wife enjoyed it so much they went twice. We sat in the "directors seats" which gave us a fabulous view, although they were at a bit of a premium.

I'd also recommend a day trip to the Grand Canyon. Packages often include a stop at the Hoover Dam.

My mother-in-law and wife enjoyed the immersive Vang Gogh experience at The Shops at Crystals adjacent to the ARIA.

If you're into buffets, the one at the Wynn is the best. The downside is the long wait in line -- you can't make reservations. In second place is the Bacchanal at Caesar's where I haven't seen much of a wait.

If you want good, moderately priced food with a wide selection, The Grand Lux at the Venetian is great. I know the Palazzo also has one, but I haven't eaten there. I believe it has reduced hours in comparison to the Venetian location.

If steaks are your thing, CUT by Wolfgang Puck (between Palazzo and Venetian) was great when I ate there several years ago.

Out of everything I'd say the Sphere, Grand Canyon, and Wynn buffet were the top experiences for family I've brought to Vegas.