Hey there, that version of MM if outdated, probably not supported by new versions of MC. You can download 4.11.0 for free there
I'm not sure if the version is the right problem, but give it a try
Vanilla mobs will act like they were programmed / made. Imagine you are not using MythicMobs. Bosses without factions will act the same. These factions are here just for making some clans or groups with these Bosses and mobs.
And no, vanilla bosses do not have factions. You must add them.