To add files to a Laird Linux build, enable "BR2_ROOTFS_OVERLAY" in your config and provide it with an absolute path to the directory you would like to overlay.  Files in this directory will be inserted relative to "/".  For example, if you would like to add files to "/etc" and the path to the overlay directory is "/buildroot/overlay", create a directory "/buildroot/overlay/etc/<files>".

Adaptive World Mode should not be used when hosting an AP.  The channel hopping algorithm can cause disconnect issues in some cases.  The best option is to set the regulatory domain in firmware manually, but at the minimum the "adaptive_ww" service should be disabled.  

Laird has added custom packages to Laird Linux.  These can be found in "menuconfig", under the "Ezurio" / "Packages" section.  

To enable a Wi-Fi bridge, select the package "BR2_PACKAGE_LRD_WIFI_BRIDGE" and then set the destination interface. For example, set the destination interface to "Ethernet" if you would like to bridge the Wi-Fi to a wired connection.