I know we've tried to figure out how your Alpena clan was related to my Essexville clan.Cathy's message may be a pretty good clue.If the Tessier dit Laforest she's seeking was from Berthier (where Simon was born before emigrating to Goderich) and moved to the very next county over from where your Frank was born just a few years later, it's possible that St-Cuthert in Berthier, PQ has records that can help you.Can't remember if you ever found Frank's baptismal records, but if it's like a few others we've seen on here lately, they took the babies back home to be baptized a year or so after they were born.
The first one I'd pursue is Francois Tessier, who was married twice at Berthier (first to Marie-Catherine Houde on 1/12/1778, second to 7/11/1796 to Therese Gervais).He was the son of Jacques Tessier and Marie-Joseph Beaudoin.Since your Frank shares the name, there's a possible familial relationship, whether father, uncle or cousin (there was a very small pool of names recycled constantly in this family).Maybe it's him, maybe it's not, but it's worth the look.
The only other son (other than Jean-Baptiste who you've already discounted) was Joseph who married Marie-Angelique Roy at L'Assomption in 1773.She'd be too old to be Frank's mom ca. 1810 and there's no info on a second marriage.
Also, as your estimated dob was a census year in the US, maybe there are some couples enumerated that could give you clues to work from in Canada.Hope it helps.