Interesting that super thin tyres seem to have fallen out of favour. Back in my early cycling days if you weren't riding on 18mm or 20mm at worst you just weren't cool, now 23mm seems to be the absolute standard. I assume this has something to do with modern materials having superior rolling resistance maybe.
Yes, and bigger too. If the wheel exists, you'll find the tyre to fit it.
Do 40mm road tyres even exist? My bike came with MTB tyres 35mm wide, which I've replaced by 25mm on the front and 27mm on the back.
This is a 1.9 (or 48.3mm)
The more traditional looking slicks come a little smaller generally, but still around 40mm usually.