The answer is yes. Check the picture above with the Urban Holster showing a Samsung Galaxy which is the largest I tried. If you have considerations for other smartphones not listed , you can check the size comparison link and use the iPhone 4, 5 or Galaxy 3 /4 as your comparison guide.
Yes. The product is made by 7 grade high quality bridle leather. So the thickness is on the heftier side to make it durable and substantial. You want to treat it as any other good leather product, including leather conditioner once in awhile.