"Luihu" means a person who is sneaky or shady, and "Katala" means devious. At least it sounds plausible to me that the author used something phonetically similar to these words, though that's purely my own guess.
Riuliu Kayara is the same guy that was transcribed as Urliu Kayara in the previous chapter (since he was bragging about writing the book there)
My guess could be Yrjö Kajala as a base name, since the humans seem to have fairly normal Finnish names, like Mikko Leminen and possibly Liina.
(But Kajala might have been picked for having been close to Katala, just like I suspect Leminen was picked for being somewhat similar to Lemminkäinen the adventurer)