I agree with you on the most part yet I have to straight out some points.
1. Today more and more scientist seem to favor the West Asian (Anatolian?) origin of Proto-Indoeuropeans, which I agree on. But it seems that Proto-IndoIranian formed somewhere in the steppes between Central Asia and Southern Russia not in the Hindukush.
"more and more scientists"? Whom in particular? I have to say, I consistently have the feeling that the Anatolian origin to me makes no sense (by the way, are you talking about an origin in Anatolia, or the Anatolian hypothesis in the sense of
Colin Renfew? The latter certainly has stiff resistence). The main problem I see is the clear abundance of non-Indo-European languages and language families in an area that is supposed to be the Proto-Indo-European homeland. Another, fairly decisive argument against an Anatolian origin was forwarded by Melchert (2012): namely that there's not a single known example of a borrowing from any of the known ancient Near Eastern languages into Proto-Anatolian. So, if not even Proto-Anatolian was possibly spoken in Anatolia, why should PIE have been spoken there at all? I personally think that an origin north of the Caucasus - in the Pontic-Caspian region makes more sense to me. This of course is "West Asia" by some definitions.
On Proto-Indo-Iranic, read closely what I wrote, because I didn't say that it was spoken near the Hindukush: I was refering to the Nuristani languages. I agree with your assessment here, I merely pointed out that an Proto-Indo-Iranic homeland in the area of modern Kurdistan was improbable based on the location of the other branches of PII.
2. The Kurds speak an Iranian language and a large part of their ancestry is most probably linked to Iranic nomads. Yet the ethnogenesis of Kurds starts earlier most probably even during the Sumerian period. The term Karda was used by Sumerians as name for the lands in Southeastern Anatolia around lake van and described a antagonistic "mountain people".
I agree on the ethnogenesis on the Kurds, yeah. But, I have to ask this regarding the term: is there any reference to this term in Assyrian, Hellenisitic, Roman or Byzantine sources? If no, then the likelihood that a connection actually exists is quite questionable. How do we know it's the same term if it has been in disuse for some 2000 years?
3. The Mitanni loandwords in Hurrian are not believed to be "Indic" since the Indo-Aryans pushed forward into India approximately at the same time the "Mitanni" appeared in Western Asia (or maybe even earlier). Most linguists today seem to agree that the Mitanni spoke a sort of Indo-Iranian dialect from a source before the language split into a Indo-Aryan and Iranian branch. Something like "Proto-Aryan"
Well, my opinion is that the Mitanni loanwords are certainly closer with Sanskrit than with the Iranian languages: this might indicate an undifferentiated Proto-Indo-Iranic dialect. On the other hand, as you may be aware, there (presumably through some late language contact) common innovations of Greek and Iranic. As you may recall, the Hurrian language is effectively contemporary to Mycenaean Greek. How likely is it that an undifferentiated PII was still spoken at that time?
By the way, I have to admit that I dislike the term "Aryan": not so much because of it's mindless misusage by the Third Reich (which might be an obvious reason), but due to it's potential for ambiguity. Depending on the context, and also the time the literature was written, "Aryan" may be interchangable with "Indo-European", "Indo-Iranian", "Iranic" or "Indic"...