McGuires of Mayo

Seeking information about the parents and Irish origins of my 3G-grandfather Michael McGuire born about 1787 in Mayo, possibly somewhere in the Westport area.  No info on parents, but he may have had a much younger brother, Charles McGuire, born about 1805.  Michael emigrated to Kitley Township, Leeds County, Upper Canada (now Ontario) in about 1836.  He married Sibie (or Zibbie) Mahon before emigrating. Known children:  Zibbie (1827), Peter (1828), Julia (1829), all born in Ireland, and John (1843) born in Canada.  Charles McGuire married Mary Alice Devlin, emigrated in about 1805, and settled in Osage County, Missouri, USA

I am fairly certain Michel McGuire is not recorded in any surviving documents (except in Canada), so this is really an appeal for assistance from anyone with local knowledge of the McGuires from that era.

Thanks in advance.

Jim Elfelt

Amarillo, Texas