I find it quite possible, even likely that the Afro-Asiatic linguistic component was originally absorbed by (or imposed onto) the Anatolian & Iranian ("northern") population that probably merged with Levant_Neolithic ones, hypothetically because they were highland immigrants in a more technologically advanced region or something like that. But that would've happened before the consolidation of a Proto-Semitic language and culture, before its expansion to other areas, probably still during the Late Neolithic,, and during that "gestation period" it's possible that the foreign elements eventually became dominant even before Proto-Semitic was spread elsewhere in the Fertile Crescent. I say that because I find it hard to believe that Afro-Asiatic came originally from too much north or east of the Levant, considering the distribution of the rest of the family (all other branches in Africa, some of them with possible older links to Southwest Asia, like Cushitic) and the heavy Natufian affinities in other heavily AA regions like North Africa and Egypt.
Just found this thread now.
Have to through my 2 cents into the room here.
There are several reasons that speak against the idea that Semitic evolved further North. At least one major reason that would ultimately force us to place the origin of Egyptian further North too.
Within the Afro Asiatic language family we have Semitic, Egyptian, Berber, Cushitic and Omotic. 4 of 5 of these are exclusively located in Africa. and 4 out of 5 are geographically very close to the South Levant. Within this family. Egyptian and Semitic have the closest relationship.
Which means that these two must have seperated from each other the latest. Egyptian is also the only language that has clear Levant_Chl influx like Semites and shares with the Semites the only other major yDNA (J) other than E1b. Also it's not like Semites are J by large majority and therefore "unlikely for them to take the "language of the local non J's.
South Levantines(Jordania as example which is the core for the hypothetical homeland) is as much E1b as it is J1.
There is no reason to assume the original Semites came from further North and East if their close relatives live West of them and their closest relative has a very similar paternal yDNA admixture to them. So this Guys (herders) from the Northeast had to have likely arrived in the Levant before Semite and Egyptian split.
And on top we have significant historic evidences which rather counter this idea. South of Mesopotamia was pretty much inhabidet by non Semite speaking Sumerians. Who are assumed to be derived from the Chalcolthic Ubaid period. When the Assyrians arrived in Mesopotamia they took over the former Sumerian lands and a huge influx on the Assyrian culture was visible. When the Assyrian King Assurbanipal invaded the North he called himself "King of the Gutian and Subarian lands".
Which clearly implicates this region was not familiar to them to begin with.
That is why the theory of a proto Afro_Asiatic homeland in the south of Levant from where the Berber, Omotic/Chadic speakers first split during the Neolithic makes more sense. The Proto Semitic/Egyptian speakers remained still behind until Iran Chalcolthic type people migrated into the region with new ideas and genes mixed into the population (The Egyptian Pyramids clearly influenced by common idea with the Mesopotamian Ziggurats). After that we see the split between Egyptians and Semitic. With the Proto Egyptian speakers moving into modern Egypt.
Of course it is also possible that after the Chadic,Omotic and Berber people split away. A group of Proto Proto Semites moved further Northeast mixed with Iran_CHL like people moved than back into the South Levant and "infected" the Proto Egyptians" before they left for Egypt.
The first theory looks allot more likely to me tbh.