I tried your way: installed BS5 Ngx64, kingroot, make the bluestack.config with root access 1 and ngx64 access 1. Lucky Patcher -> Patched the login thing as usual, pach applied, then uninstalled kingroot and luckypatcher, installed the original version of the game, logged in with google, then made the config turn to value 0 again and tried to install the MOD version: both signed and unsigned failed.
Tried to put values on 1 for root and install both MOD versions on top of the original version: both failed again.