Do they need to be stretch?
My granddaughter went through a period of "no zippers or buttons" at school because she wanted to get into and out of the school restroom quickly. She was afraid someone would come in while she was in there.
We made her a lot of shorts, capris and long pants with elastic at the top. You can get soft wide elastic for the waistband. That would let you use every beautiful and sunny piece of fabric you can think of.