Urth Digest, Vol 76, Issue 169

I agree that Auk is very likely to be an embryo. He has exceptional abilities, and the gods take an interest in him which can't obviously be explained by his situation in life. I also suspect that Mint was his surrogate mother. This explains the special interest she takes in him, and the way he sometimes thinks of her as a mother, while not conflicting with the undoubted fact that she is a virgin. (She would have to have been very young; but Mucor was very young when she gave birth to the lynxes. We know she had some kind of traumatic experience before becoming a sibyl.) Of course, this leads to more puzzlement - the two undoubted embryos we know of, Silk and Mucor, both had wealthy sponsors; who could Auk's sponsor be? Regarding the origin of the embryos, though, Crane says that Mucor's parents 'probably met in a petri dish', implying that they are the result of in vitro fertilisation rather than clones. ('How would he know?', you may ask. But if enough is known about the embryos that people can find out what they were bred for, it's not impossible that their origin is known as well.)

In the abstract, no. In context I don't think it's too much of a problem. Tartaros does tell him to let Hyacinth go - this is explicit - and 'explains' this by saying that he has healed Auk's mind as much as possible. I take it the point is that he can now tell Auk to let her go because, having recovered from his injury, he can work out what he ought to be doing. (Also Tartaros earlier said he was able to communicate with Auk because of his injury. I don't think it's exactly possession - he holds Auk's hand, for instance, which isn't at all like what Chenille experienced when possessed.)