Yes, all pro models (plus the Fold) from the Pixel 6 series onwards have UWB support. And at least on my Fold, can be toggled on and off under "Connection preferences". However, I don't believe there is currently any system feature that actually utilizes it yet.

To be honest, I'm actually a little disappointed they didn’t opt to include the thermometer in the upcoming Pixel Fold 2. Especially, since it’s going to be branded as the 9 Pro Fold.

Yes, the next version of OneUI should still support lockscreen widgets. This should only affect the stock builds of Android.