Are the Emims, like the Anakims, mentioned in the Bible really Anunnaki, or children of the Anunnaki?

These are Anunnaki as well. The Anunnaki at that period of history had a larger presence as physical beings and were given various names by the humans they encountered. This was a form of subterfuge to disguise their true origins and not give greater awareness to humans of their true nature. They were widely accepted as gods and superior beings and people quickly learned to fear them, so the attribution of a name was a convenience of that time and place and not a truth as to the race of beings truly represented. You can assume that any group referenced in the Bible as giants, were Anunnaki. There were some tribes of human of tall stature, but not extremely tall to the extent of the Anunnaki. So there may be some grey area, but the recollection of giant races and these two designations, you can be sure were Anunnaki, one hundred percent.