I wrote about the XIV century map.
I must have misunderstood then. How does the 14th century map confirms that Khotyn, Chernivtsi, northern Bukovyna, Pocutia must belong to Halych or have a significant Halychian/Ruthenian majority in 1337, when there are no settlements left in the region in the 14th century but they used to be in the 9th century before the Vlach migration? seems counter-intuitive.
We have 2 confirmed Vlach voivodships
(sort-of duchies) in the region in 1337, in Onut (near Hotin) and Hansca (in the Lăpușnei region). They are mentioned to be ruled by Vlachs, meaning it couldn't have been part of Halych as they are listed as vassals to the Golden Horde and had a significant Vlach population else they wouldn't be ruled by a Vlach.
We also have further mentions of
"tari" and
"codrii" in in Onut, Bacota, Ușița, Cucelmin, Calius and North Bukovina, these essentially were Vlach political formations smaller than a voivodship.
We also have Niketas Choniates's chronicle about the Vlachs who captured Andronikos Komnenus in 1164 at the borders of Galicia. And the book Medieval Towns in the Romanian Principalities says that in 1352, the south-east border of Poland had reached the Ceremu river, near the lands inhabited by Romanians.
All of these point out to a significant Vlach population in the 14th century.
I believe there was a Ruthenian population in northern Moldavia, as also shown by the 14th century map with the remaining settlements, but it couldn't have been under Halych or ruled by Ruthenians as we have historical sources telling otherwise.
And given the mentions of Vlachs and especially the regions being ruled by Vlachs rather than Ruthenians, I believe it's more likely that the Vlachs were the majority in the region, although both populations existed.