Note: I hike in Florida, and our most imposing elevation change here is under 300 ft, total.
With that being said, I hike in a Keen-style sandal that has toebox protection (this came out of my need for a bike shoe that drained well in the rain). No need for socks when the temperatures are above freezing (despite being a hot-natured guy, my toes freeze easily), and they dry within a quarter mile to an half mile after stream or swamp crossings. I have athlete's foot problems with closed shoes over long periods, and these have yet to give me trouble with that on the trail.
Mine weigh 700 g/27 oz for the pair (size 9.5). So, not ultralight, but they were also $5 at Wallyworld.
I still bring thick socks for sleeping in when the temperatures are forecast below 60 F, but that's a separate issue.