The Flexibility of "A Villain Named Z_rg"

How flexible is A Villain Named "Z__rg"? I'm asking because it looks like the description is saying these three consonants are important to the trope. Namely, starting with a sibilant, having an approximant ("are" or "elle" sounds) somewhere in the word, and ending with a velar stop (a "g" or "k" sound). The trope specifies that it's these sounds, or phonemes, that compose the trope, hence my question.

But some examples don't have a stop at the end (e.g. Zarrko, Klingon) or a stop at all (e.g. Xur), whereas others don't have a sibilant at the beginning (e.g. Bolg) or an approximant in them at all (e.g. Zygon). Others only have one (e.g. Xenu, Xamot, Kang [which ends with a velar nasal]).

I figure this is flexible enough to include cases where the three phonemes are there but in different orders (e.g. Gargantus, Kahless, Dragos, etc.), but the other names don't seem to fit.

I would say that if you use an 'X' instead of a 'Z' then it still fits. Still harsh, still alien sounding, still Xtreme Kool Letterz.

I wouldn't include words with clear normal derivatives, like Gargantus and Dragos. Not sure about Kahless, but it seems rather different from the trope to me. Likewise with Klingon and Kang.

The trope is about a specific pattern of names, not just those that sound kind of harsh or kind of alien.