I may have read ahead a bit and prepared some thoughts!
Note that on the cover the logo is in the right place, but has been altered to Katakana. We're still being eased into the different cover style per issue territory.
This issue references three things from Japanese culture - one ficitonal, two historical.
The fictional one is, of course Kaiju Eiga, or monster movies. Specifically the Godzilla series. Island Zero is a stand-in for Monster Island, and the cultists encounter the remains of Mothra, Gidorah and Godzilla in turn. At the end of the episode the living monster is Rodan (the source of a hilarious homophonic discussion between myself and a tipsy Mrs Lorcan a few weeks back where she thought I was talking about Rodin).
The writer and his acolytes are based on Yukio Mishima and his Tatenokai. Born in 1925 to an offhsoot of a noble family, Mishima was raised primarily by his aristocratic grandmother, who frequently made fatalistic outbursts while his father was obsesed with masculinity. These primary influences on his childhood lead to his own obsessions and also to conduct his early writing in secret, lest his father find his 'effiminate' manuscripts and destroy them. As he found his footing as a writer Mishima would begin to become obsessed with sexuality (he was married and had children, but a fellow writer alleged they had a gay relationship, and he cruised gay bars in Tokyo while researching one novel), and physical fitness and bodybuilding.
In 1967 he joined the Self-Defence Force, founding the Tatenokai private militia the following year. The Tatenokai swore loyalty to the notion of the Emperor rather than the individual - Mishima was opposed to Hirohito renouncing his divinity as part of the surrender terms. And then in 1970 he and four members of the Tatenokai took the commandant of the Tokyo Headquarters of the JSDF hostage, and delivered a speech to the soldiers in the base intended to inspire them to stage a coup. This speech was ignored or mocked for the most part, and Mishima and one of his followers committed suicide by seppuku (the individual kneels, slices open their belly and is then beheaded by a designated 'executioner' before they show too much pain) thereafter. Ellis also wrote about Mishima in issue 42 of Stormwatch vol. 1.
The sarin gas in the bag is a reference to the Aum Shinryko cult. In 1994 they killed three people with homemade sarin and VX, and the in 1995 they released sarin on three lines of the Tokyo subway, killing 12, injuring 50 and causing temporary vision problems for 5,000.
Arguably, the cult leader's lines about shriveling of genitals and his cannibalism could be references to Japan's reputation for weird sex, especially his bit about eating a girlfriend raw in a Tokyo sex club.
The guards who show up are members of The Four's organisation, as we'll see in a few issues.
Overall I agree with @Tom_Punk in that there's very little meat to this issue. But I'll acknowledge that it's an awful/hilarious turn of phrase for an issue where a cannibal brings his followers to eat monster corpses. The plot structure here is the same as issue 1's back half - Pleanetary go to weird thing, and see weird thing. Jakita and Drums know at least a little more than Snow does and fill him on some of the blanks. The deconstruction/reimagining element here feels more like Ellis bursting the baloon on the Kaiju genre - that most of these monsters are one of a kind, and even if you leave aside that they could never exist in reality, they'd all die sooner or later - than analysing or recontextualising like Doc Brass vs the Justice League, or, say the issue about the British Invasion. It's a very slight issue, and I feel like Ellis especially is still working out exactly what he wants to do with the book.