Now that we are davening b’yichidus, I heard that I may lain that week’s parasha from a chumash But may I say Hashem’s Name ? and if so , can it be counted towards shna’im mikra v’echad targum?
Yes you may definitely say H-shem’s name when reading the parsha, in fact you should specifically say H-shem’s name, as that is the correct way to read the posuk. You can count it as part of shanyim mikra.
Whenever someone says a posuk he may say shem H-shem. Regarding reading from a chumash see M:B 143-9. Regarding shanyim mikra it is brought in the name of R’ S. Kaminetsky shlit”a that doing shnayim mikra will suffice for this- obviously it can be counted for shayim mikra.