Is this the right plugin for me?

First of i wonder if this plugin are able to do what i want, that being have majority of mobs in vanilla minecraft spawn at night,

so mobs that are normaly limited to nether etc, blaze, wither ghast and such would be able to spawn in the reg world

This far ive tried to add Blaze, Giant, and Wither all have appear fine on the mob list, worked with spawner, only the default skeleton king have spawned by itself,

starting to wonder if im going crazy or just the plugin that is broken or...

Is this the right plugin for me?