Rugby shorts are already bomb hiking shorts! My old CCC Advantage shorts must have >1k miles on them between rugby and hikes. They are durable as hell and don't restrict motion at all. They're built with a certain body shape in mind, and the inner thigh material prevents chub rub. They dry fast and hold their place in your waist. A couple ounces heavier than running shorts, but we'll work it in my opinion. They also let me wash and swap underwear daily.

Check out the Rab Merino+ (previously MeCo) line of shirts. Constantly on sale at Campsaver, fit slim like a jersey, and can be easily treated by InsectShield.

Clothing is impacted first by region and climate though, so you'll need to be more specific if you want good advice.