Halbarad arrived in Rohan with thirty Dunedain, plus Elladan and Elrohir. (RotK chapter 2,)

He doesn't mention any who started out with him and didn't make it, but then as soon as he and Aragorn meet, they have strategy to discuss. They'll speak of lost kinsmen at a later time, in private.

Of all the 30 Dunedain who come to Rohan, only Halbarad himself is named by Tolkien; and he is the only one who is mentioned as dying on the Pelennor Fields.

As to which of the Dunedain invented by Turbine will live or die, we won't know till they tell us.