Yes, confusing..but agree it must be a hard one to research as it is most odd that 4 children are written & transcribed badly, Jessie May, William & John as Baber and then Sarah as Baker, on the FHS site...

Perhaps Smiths are still the hardest though...

I do see your dilemma if you are looking to find more Mary Jane Belworthy as I see she doesn't appear to be registered as Mary Jane, although it is always used on census.
There are no other Belworthy to be found in Ontario so she appears to have come on her own.