Albert's grandpa was actually my great-grandma's young brother. So your line and mine do actually fit together :-)
The change to Tacey started circa 1860. They disappeared from Goderich ON into the Quanicasee area of the Saginaw bay (not that long of a long trek) in the late 1850s. There they hid out for several years on an island just far enough offshore that no one knew they were there. Eventually the logging industry caught up with them and they were found in time for the mid-decade state census. The census was the first time the spelling TACEY was used. The state census taker was a little better versed in French and got it a little closer than the federal census takers. Parish records remained TESSIER until the 1870s.