There are a couple of premises I'd dispute there.
In the book, the reverence for living things is because they are so rare and don't exist any more. There is a longing for contact with real life, so part of that desire and longing is because they are so rare.
"I'd kill the wasp" is not, actually, the expected answer. The answer is irrelevant. The response is blood flow, pupil dilation.... physiological and emotional responses to the questions. The Nexus models up through 7, though physically and intellectually powerful, are emotionally stunted because they have almost no time to learn and develop normal human emotions. The test is looking for exaggerated or inappropriate emotional responses. The actual verbiage of the response is irrelevant. Also, since pretty much all animal life forms seem to be of synthetic origin, I'm not sure why you'd make the assumption that the hypothetical wasp is non-synthetic.
Tyrell: "Capillary dilation of the so-called 'blush response', fluctuation of the pupil, involuntary dilation of the iris."
Deckard: "We call it Voight-Kampff for short."
Oysters are long rumored to be an aphrodisiac. There is probably some sort of decadent sexual or sensual implication in the setting of the scene that is supposed to provoke a reaction, more than oysters as a life form.
Scientists say raw oysters are really an aphrodisiac - Telegraph (UK)
It's not a fish scale, and not an organic scale, either. He finds the scale, which has a origin code embedded on it, and tracks it back to the person who makes artificial snakes. That person tells him who he sold it to, which is how he tracks down the replicant, Zhora, who is working as an exotic/erotic dancer where, apparently, she uses the snake in graphic ways as part of her act.
EXT. ANIMAL ROW - NIGHT
An aquarium full of fish, weird looking fish, the kind that might eat each other. They're gliding in sinister clusters like Doberman pinschers with gills.
The CAMBODIAN LADY is a withered woman in black. She's got a lens in her eye and she's looking at the flake which is on the tip of her finger.
Not fish! Snake !
MICROSCOPIC VIEW - NIGHT
We are looking at a huge enlargement of a snake scale seen through a microscope.. but we don't know that. It's just a grand abstract weirdness blurring and sharpening and changing.
EGYPTIAN (OS): The finest quality, yeeeeeeessssss. Perfect workmanship. Geniune artificial snake.
The flake becomes a landscape of forests and moonscapes. Buried deep in the texture of the thing is a serial number.
EGYPTIAN (OS): Serial Number 99069745xb7Y. That would indicate a Crotalus Atrox......
Dailyscript.com: Blade Runner (screenplay, not transcript)
And from a script that more matches the final movie....
[Deckard returns to Taffy's]
Announcer: Ladies and Gentlemen. Taffy Lewis presents Miss Salomé and the snake. Watch her take the pleasures from the serpent that once corrupted man.
Script: Blade Runner
The grubs are specifically raised/generated/farmed as a biologically efficient protein source. They were made to be eaten. It's this particular solution and technique that made Wallace the uber-wealthy savior of humanity. Since the grubs raised on the farm are made for human consumption, eating them is not somehow out of character for anyone.