I’m not able to help you with you search but my ancestors are from Minsk as well. Would you be able to share the name of the archivist who helped you go back to 1740! That’s amazing. I can’t get past my Great Grandparents sadly. Also if you could give me an idea of how much they charge. Thanks so much! Good luck with your search.
Lashinsky/Laschinsky/Leshinsky from Minsk, Belarus