I never caught on! Now, I wonder about the others...
Ah, thank you. The first few (Mary, Crowven, and Twyla) I figured out—though in Mary's case, only because someone pointed out the pun in her name. Given Reginald's surname, I can see Pufferfish (Tetra, as a play on "Tetrodotoxin"). Vasilis is still a mystery to me, even so. But that does nothing to diminish my appreciation!