The title's English translation is slightly off. The construction ゴーレムの蛮妃 is using the particle の in the role of indicating identity/apposition (e.g. 大統領のブッシュ氏 = "the President, Mr. Bush"), i.e. an accurate translation should be "the Golem Barbarian Queen" (or, more long-windedly, "the Golem that is/was the Barbarian Queen").
Nah, I think the golem becomes the elf girl for sure, both are white, the golem blush in the start, the skeleton under the stone is a girl, the golem fears that scene... the soul of the girl/skeleton got into the golem or something