We can speak long time about linguistic aspects without reaching any definitive result, because linguistic is a "weak" science.
Linguistics is not a "weak" science. Historic linguistics is, as the name says, a historic science, but that doesn't mean that its any way less scientific (there are such concepts like sound correspondence and sound laws). Its not a free-for-all licence to twist and bend things like you want them...
Maybe Vindo for Celtic people in "white", but for Veneti is simply their own name (for example welsh Gwyn can refer also to a Veneti tribe, - a colony of Veneti coming from Brittany).
Sorry, but that's just hair-raising wrong. The element *windo- is thoroughly attested in the Celtic languages (e.g. "Vindolanda", "Vindomagus", etc.), including - like I said - in modern Celtic languages. What you're doing with the Vindelici is that you ad-hoc dismantle the name in a different way (to basically claim your element) and link it. Again, you're basing this solely on superficial similarity of the names, without any care what language the Vindelici might have spoken based on other sources (place names, personal names, etc.). You just say that they must be related related with the others based on superficial similarity. You are doing the same with the name "Slo
veni", and no offense, but what you're doing there - that's not methodologically sound by any means, that's just fooling yourself.
Also, as I mentioned, the linguistic results are there, and they don't offer the room of speculation that you'd like them to have:
1) the Veneti of Gaul are presumed to have been Gaulish based on place names and personal names. There's no evidence for another ("Venetic") ancient language, and Gvozdanovich's analysis of a modern Breton dialect is irrelevant because Breton arrived there only during the Migration Period, and the ancestor language was actually spoken on the other side of the Channel.
2) the Adriatic Venetic language is attested from inscriptions, and can be shown to be an Indo-European language most similar to the Italic languages, although some similarities to the Germanic languages also exist. I should reiterate here that Gvozdanovich's hypothesis that Adriatic Venetic was particularly closer with Celtic appears implausible on the ground that it does not share the key sound developments.
3) For Baltic Veneti (Venedi), about their language is we know the least, but they can be assumed to have been Baltic (ot Balto-Slavic) based on the fact that Baltic-speaking tribes of identical name inhabit the area around 1000 years later.
Only when languages and genetics match together we are in the right way, so what we can say at the moment is just that Gvozdanovich thesis and the map of R1a Z92 are compatible and coincident. In East Germany you know very well the Bronze age settlements of Lusatian culture. Later happens that German tribes with war and crusades took the lands of pacific and hospitable Wendi people (Ptolomys Venedi).
I also would say that genetics, as of the moment still stands on a lot more shaky legs (although that has improved considerably in recent years thanks to more and more samples of ancient DNA) than historical linguistics, mainly by the merit of being a still relatively new science. Still, what you're doing is dubious at best, because, who determines what "the right way" is, it seems very subjective to me. In genetics, find it dubious if you look at modern distribution patterns and try to link that to a single event, or single ethnic group. If anything, modern distribution patterns must be the "sum of all history".
