I bet there are more animals that you don't eat than you do, and maybe there are even more that you would not be prepared to eat than you would.
I would consider heating human. I have nothing against another mammal. However, I would require humane treatment of said human (or any animal or byproduct I eat).
I'm not going to pretend I'm some morally superior being. But I'd like to at least reduce suffering of beings. After all, something else must die for me to eat (and I can't live on milk and honey).
They would revert back to natural tool users with each succeeding generation. As an order, they wouldn't even be able to dominate house cats.
We don't know, but most studies that look at what does well in acidic oceans come up with jelly fish. Lots of jelly fish.
Yum, heavy metal infused jelly fish...