Hi all you Marchesseault cousins! I finally found the key piece of info to finding my Great-Great-Grandfather!
All this time, my grandparents and I thought we were looking for Achille or Archie Marchesseault. It turns out his name was Joseph Archille Marchesseault! So, if you have any info on him and his wife, Delia Rose Guay, let me know!