Yes, I started with a custom build (Selinux, luci-Openssl, wpad-openssl, odhcpd full, etc) then I updated with Attended Sysupgrade to the newest snapshot.
Did you try using the Banana pi release, then do a sysupgrade for latest snapshot (From nand), then copy the updated version to emcc?
I use my bpi-r3 as an AP, all dhcp, adblock, tor, firewall, dnsec, is done by an Openwrt x86 n5105.