You have done an exc job of locatting your ancestral hamlet. Many people just throw their hands up.
Alex/Alexey/Oleksa Kowal born in Velyka Kharucha (Велика Харуча) > Vohlynskaya gubernia/region > Tzarist Russia.
Kowal (Коваль in Ukr.) is a very common surname in Ukraine, It is an occupational surname and means BLACKSMTH, equivalent to Smith in English.
Your ancestral village Velyka Kharucha was first documented in 1544. Today it stll exists as a hamlet with 321 residents. It has been renamed selo/village Kolodiyivka (Колодіївка). It is clustered w/Velyki Mezhyrichi, w/which it shares the Village Administration and Post Ofc. It has a school of 2 grades, a cultural club and its own church. During the Sovet Period it received recogniton as the village that grew the biggest beets in SSR Ukraine. Velyki Mezhyrchi draws tourists here because of the 18th century Stetsko Palace, an architectural landmark, that stands on the hill. I tried findng photos of Kolodiyivka, but w/o
Most importantly, yes there are still surviving Koval living there. I was not able to obtain a specific list, but they are there.
What religion did Grandfather practice?