Just some crazy ideas

I actually haven't used AdAway for a while, but regarding the specific IP mapping of a host, is there a way to modify the host file header (assuming root)? ie where the local host mappings are. Its the obvious place to put host to specific IP mapping like
@markd89 is looking to do, and most host builders I have used have the feature. The other way I can think of (for root) is to run a shell script after each build to add them into the end. Or, since you are on root, adding a boot script to the host file module wouldn't be hard. But I am not sure about the timing of boot and mounting the file. ie would it be mounted before being modified by the script.
As for non-root, for which I have NO experience. Maybe look at the adaway SQLite db to see if there is somewhere it could be inserted there.