I would call the Chameleon "Proteus", after the Greek sea god who can shapeshift. The Giant Bat is a sick concept, I would probably call it Urusai, after the Japanese word for screech.

Also I think the "Giant Cicada" is just called "Cicada" (the second form), the organism itself is called "Megapede."

Personally, I prefer Chameleon's original name as it worked well enough; my issue instead been with the ones that have the words "Giant" and/or "Mutant" in their name.

For the Cicada, I'll probably rename it "Megacada" to keep the theme from its first form, Megapede.

Additionally, I like your alternative name for the Giant Bat. That said, since its first attack is in Nigera, maybe instead go for "Skree" (the Afrikaans translation of Screech).

I'd call the turtle "Zaratan" named after a cryptid.

That's a pretty good one.

I could think of many names for the Giant Turtle, but none of them would be appropriate.

(Yeah, I'm still salty about what he did to Komodithrax and her baby).

As for a proper name, and assuming both Dark Horse and Toho were okay with it, I'd probably call the giant turtle "Kamerus" - after the snapping turtle kaiju that cameoed in some of the Dark Horse Godzilla comics (since the Giant Turtle is believed to be a homage to Anguirus and the word "Kame" means "Turtle" in Japanese).

Additionally, for the Mutant Squids - which would be bigger than both Giant and Colossal Squids - I'd probably call them "Titan Squids" to clarify their size.

Looking back at this thread, I'd probably give the "Fire Monster" the name "Gigantis" - since I've seen a fair few people make that joke as a reference to the Americanized version of Godzilla Raids Again.

For the largest of the Giant Mutant Black Widow Spiders, I'd probably call her "Queen Widow" - since she's responsible for the birth of all the other spiders.

For the Mutant Jellyfish, which looks more like a Mutant Jelly Prawn, I'd probably name it "Sergasta" after the species' name.