So we kind of agree on all points. As I said looking at Yfull it is evident that the diversity boom happened around LBA-IA. Hence I tend to follow the cremation line of thinking. I would question it if we had any other homeland for E-V13, say steppe, Central Europe or Anatolia but so far the indication is that it is local to the Balkan-Carpathian region, hence if it was there and we have no samples one has to concede that cremation is the best hypothesis.
The Carpathian basin was also one of the primary source regions for cremation. So its not just that cremation appeared there too, it was the main rite of the local population throughout the ages, even when other people abandoned it.
And the difference is particularly striking to Illyrians:
- Illyrians had collective clan tumuli, into which the members of the clan being buried with great care
- Thracians oftentims had not even a proper individual burial, but quite often scattered the ashes of the burnt remains on ritual places, so that not even an urn cemetery can be investigated!
And that tradition we later hear and can testify archaeologically from Northern Dacians already appeared in the Carpatho-Balkan zone thousands of years earlier, especially in the Upper Tisza/Carpathian Nyirseg group, which I think could be directly ancestral, the main group of E-V13 in the EBA:
Ny?rs?g and Sanislău are both characterised by cremation burials in urns which almost always occur singly or in small groups. Indications for burials where the ashes was scattered are as uncertain as the cultural attribution of two inhumation burials (due to the lack of decorated vessels. Kalicz 1984, 111; Dani 1997, 56f.).
http://www.donau-archaeologie.de/doku.php/kulturen/nyirseg_english_version
Even if inhumation burials appear, which could be tested, they are more likely than not foreigners. Same goes for G?va.
We have the same pattern in the opposite direction, like in Vekerzug the same area which was the home to Nyirseg and G?va was still cremating, forming an own Thracian Vekerzug province. There were occasionally inhumations in their territory, but they clearly were no locals or at least unusual, untypical burials. The same goes for the Western groups, which preferred inhumation, sometimes appeared cremations of the Eastern group's style. Clearly, this rather points to exchange between the Vekerzug provinces, but the more clearly Thracian and therefore more likely E-V13 associated Western group was just cremating.
This means even in a wider cultural sphere, like Hallstatt or Vekerzug, the specific groups more likely to have increased E-V13, like in Vekerzug the Eastern province, and for Eastern Hallstatt the Fr?g group, did as a rule cremate and can't be properly tested. Like we will get more Vekerzug and Hallstatt samples which are less likely to carry E-V13, throughout the whole Iron Age.
There are just a couple of exceptions, and those need to be looked at most carefully, like Thraco-Cimmerian local Mezocsat samples, Basarabi, Psenichevo (already E-V13) and Babadag inhumation burials.
A lot of the Urnfield cultures beliefs and rites seems to have an origin in the Carpathian basin. So they spread the cremation rite to others, including Slavs and Germanics (transmitted by Lusatians and Western Urnfield groups).
MBA-LBA-EIA i bet on Balkan-Carpathian horizont. From Vatin-Belegis to Gava/Ottomany/Wietenberg. South/West to North/East cline.
Beyond MBA i cannot say anything, i would even say in Early Bronze Age E-V13 could have been even more inland Balkans, say Bubanj-Hum. But, at this stage i don't bet on anything. But, i can exclude Steppe and Anatolia for sure otherwise we could have seen old subclades from there, but not the case.
Bubanj-Hum is a candidate, but I think, if it was more Southern, it will be more South Eastern, rather, like in the direction of Southern, Transcarpathian Romania. But at the moment a more Northern centre, like around Ukraine Transcarpathia, NW-Romania, NE-Hungary, very SE-Slovakia, is the most likely candidate. Because there we have a continuous, less disturbed, local element, from Mak? into Nyirseg, into Otomani -> Suciu de Sus/Lapus/Berkesz-Demecser -> G?va/Channelled Ware.
But again, if more Southern, I would check areas like Oltenia first:
https://en.wikipedia.org/wiki/Oltenia#/media/File:Lesser_Wallachia.svg