Is the ability to toggle WPS present in LuCI in the latest builds of LEDE? I'm currently on OpenWrt 15.05, and I found it a bit strange that it wasn't (I know it's not secure, but it should still be an option).
WPS doesn't work out of the box on OpenWrt or LEDE, you need to remove wpad-mini and install wpad and hostapd-utils, reboot, and then you should see the option to enable WPS in Luci under Network>Wireless>Wireless Security. In my experience, WPS actually working is hit or miss, although it works fine on my WRT1200 v1 on LEDE.
- Remove "wpad-basic-wolfssl"
- Install "wpad-wolfssl" and "hostapd-utils"
NB: You can install vanilla "wpad" instead but you won't get WPA3-SAE or other advanced SSL setings for Wifi.