Has the narcissistic troll posed that great a threat here?
As a prominent researcher (see my previous post in this thread) on Internet troll personalities, I know nothing of this taxonomy. All trolls are somewhat narcissistic in their craving for attention and cunning use of diversions to generate heat (excitement for them). However, distinguishing trolls as narcissistic, obsessive-compulsive, or deluded is usually no different than distinguishing them as young, hairy, or brilliant. It is a distinction in that these are personal attributes, but they aren't broad categories against which trolls cleave.
I would say your troll is narcissistic in addition to being a troll if he or she shows clears signs of the narcissistic psychopathology: habitual lying, condescending attitude, manipulation, need for praise/attention, and a sense of being entitled to things without requisite effort. These items must go beyond, for example, the inflammatory posts and concealment of identity and intentions of the garden (or maybe I should say lawn
) Internet troll.