I would disagree with the Hunnic corpus being predominantly Scythian (i.e. Indo-European/Caucasoid);
The Germanic vassals of the Huns ultimately rebelled and overthrew them (Nedao/Bassianae) after Attila's death; And if we look at Germanic (Gepidae/Heruli/Ostrogothic) cemeteries in that post-era there are a decent amount of Mongoloid skulls and skulls with such features found;
Department of Anthropology - Hungarian Natural History Museum, Budapest - (2000)
http://www2.sci.u-szeged.hu/ABS/Acta HP/44-87.pdf
Undoubtably these burials are Huns - subjugated/captured remnants of the by now independent Germanic vassals; Based on that i derive the Huns to be most prob. a Turkic/Mongoloid people - and if they subjugated Scythians further east (i.e. before emerging at the Don river) than that must have been just a part of the Scythians and def. not the entire branch of them;
Im also not sure as to how many Scythians were still roaming the eastern steppes in 3rd/4th cen AD;
Given that there was already a large exodus of Scythians (coppled to the Cimmerians) more than a thousand years earlier (SargonII/Nineveh) into the South Caucasus and Iranian-plateau plus extending to the Saka kingdom in Indus-valley further later;
I do agree that Cumans/Kipchaks
pos. also Bulgars and Avars are most prob. Indo-Europeans (Scythian/Sarmatian remnants) that were subjugated and Turkofied in the process further east (Caspian/Volga area) - but at a much later time;