The dog is probably a weird version of Anubis? Anubis always wears the double crown, at any rate.

I checked the BPL website to see if they said, and they didn't; what they did say was that Flaubert was explicitly Sargent's source for the Carthaginian stuff, so nice eye.

From divagations into obscure portions of the net, I can say with some certainty that castrato is indeed a gender identity that exists today, and also that you probably do not want to know the details.