No monsters are spawning naturally in the main world, its nether, or its end. They spawn from spawners and plugins just fine, but not naturally, as in by minecraft's main default method.
Latest Log Part 1: http://pastebin.com/jVkX4vhL
Latest Log Part 2: http://pastebin.com/Q1FUgCJh
Latest Log Part 3: http://pastebin.com/7wSGC0Xe
Latest Log Part 4: http://pastebin.com/jckKmNQU
Latest Log Part 5: http://pastebin.com/08pL22KW