Carhartt Men's Loose Fit Washed Duck Utility Work Pant

I have a 2 inch wide belt....Is that going to fit on the belt loops of these pants?

Are these canvas?

What is up with the sizing? I ordered 36x34 first which is what I normally wear and they were tight. then i ordered 38x34 and I had 3” extra

Are the knees reinforced? Double layer?