TimexMen's Expedition Field 43mm Watch - Brown Strap Black Dial Gunmetal Case

Will a 16-20MM band with work with this watch? Looking to replace the band.

The black case is plactic or metallic?

Is it leather stap?

In case I want to have a different color band, how can I look for it, and is it easily replaced in case I want to use a different band each day?