No. The documents they wrote were in Slavic not Romanian. Their personal names don't have more than 3-5 % of Vlach names. These "Vlachs" were not speakers of Romanian.
Vlachs which coming to Bosnia, Croatia etc have ties to southeastern Europe. Probably hills towards Albania and Greece. Other groups of Vlachs are probably coming from direction of Romania. There are several groups of Vlachs and directions of their migrations to the Western Balkans.
As for the fact that some of their documents were in Slavic, or names etc, it has nothing to do with their origin. Vlachs live in the area of Slavic lands and assimilation goes in all directions. What we can say with certainty is that the original Vlachs are not Serbs. In Bosnia and Croatia they later become Serbs and part also Croats etc.
Slavic underclass became Vlachs in the way of life and status and they assimilated the original Vlachs.
This is about assimilation which going in all directions. As for Vlachs status this may later be the case for all population of the hilly cattle-breeding Balkans but the Vlachs still have their original Balkan origin which is not related to the Slavs. As I said, it is more related to Albanians and even Greeks. I am talking here about the Vlachs of Southeast Europe. Romanian Vlachs have their own directions of migration.
Do you have any idea how the Romanian personal names looked like? Ciribiri from Istria are Romanian speakers, and their personal names from 16th century were very different from these Vlachs.
As I say, the question is which Vlachs are involved. Romanian, Greek, Albanian, Serbian, etc. So their names can be different but one language, etc, etc.
Some of these Serbs in Vlach status include even various modern Croat families.
There are no Serbs
in Vlach status in general. There are probably Serbs, Croats, Albanians, etc in Vlachs groups but they have nothing to do with the Serbs.
Promotion of
"Vlach status" in Serbian historiography is mostly because most Serbs are actually of Vlach descent which have nothing to do with the original Serbs. Since these are large numbers, they call it "Status"(so that no one would think of another origin of Serbs). That's what academician Noel Malcolm or Polish historian
Ilona Czamańska claim
. Or Croatian-American historian Ivo Banac in his book which won first prize in America for year 83. See:
https://en.wikipedia.org/wiki/Vlachs_in_medieval_Bosnia_and_Herzegovina#Legacy
Some of these Serbs in Vlach status include even various modern Croat families. Take a look for example at the old family of Poropat. Who belong to I-PH908>Y84307 , they have relatives in Serbs, as do most Croat PH908 (as all Balkan PH908 are proto-Serbs just as all R-Z2705 are proto-Albanians).
Unfortunately
I-PH908 has nothing to do with proto Serbs. This mutation has no source in Lusatian Sorbs or Lusatia. For now, this mutation, like the others in the branch S17250 very likely have to do with proto Croats or White Croats which coming to Roman Dalmatia and later become this or that.
See
https://www.eupedia.com/forum/threads/31539-Genetics-confirm-migration-of-White-Croats-to-Croatia
From Serbian DNA project admin, I just pasted it in google translate, I don't have time to do it myself.
He is talking about the Vlachs of Istria, whose descendants are the Poropats, who were Catholicised early.
Serbian DNA
project is only good for raw genetic data. Everything else is not usable for some big conclusions. They address their audience.
There was lot of Albanian influence in these Vlachs. One example is the line I mentioned. E-Y161799, and it has Serb from Bosnia, Serbs from Dalmatia under E-BY4455 (even one Croat I think possibly), also there is one Romanian E-BY4455*. So these are proto-Albanians who became Vlachs, and then Serbs.
It is an assimilation which goes in all directions. I've talked about that before.
But they lost their Vlach language in 14th century already. They spoke Serbian when they arrived to Croatia.
They do not speak Serbian when they come to Croatia. They speak the Slavic language. Where they adopted that Slavic language is a question. Whether it is from before ie from the Slavs of Greece, or from Macedonia, Montenegro, southern Serbia, Croatia, etc.
Take Medieval Herzegovina "Vlachs", their groups being designated as Vlachs already in 14th, 15th century. They too carried 90+ % of Slavic names, their inscriptions were in Serbian.
First we need to see what it's about (
their inscriptions)? Like I said it’s assimilation. However, they have nothing to do with the Serbs in terms of common origin, ie that the Vlachs would actually be Serbs.
And their Y-DNA is mostly Slavic.
Yes, that's the assimilation we were talking about. The Vlachs also became part of the Slavs.
These Vlachs were already Serbianized in 13th/14th century.
These are probably parts of the Vlachs that were under Serbian rule. However assimilation took place a century or two later. According to Austrian historian Karl Kaser Vlachs in Croatia were assimilated into the Serbian ethnos during the 17th century. Also in Croatian, etc.