Have you tried looking in the Springfield vital records?If Thomas's birth isn't recorded there, I would hazard a guess that he might well have been born in another nearby town, the name of which would have meant nothing to people in Ontario.Accordingly, he might have given "Springfield" as his birthplace as shorthand for "an obscure village in the middle Connecticut Valley."My great great grandmother Perrin told her descendants that she was from "Troy, New York," when in fact her home town of Granville was many miles from Troy.Troy was just the nearest city.
Unfortunately, it doesn't appear that the vital records of more than one of the towns of Hampden County are easily available online.(The only one that is available on US GenWeb has no Perrins at all.)
Sometimes the church records fill in gaps in the town vital records. That's true in Hebron, where Thomas's Aunt Anna Perrin is recorded only in the papers of Gilead Church (chr 1773); not in the town VR.
Anyway, I have no doubt but that your Canadian Thomas is the "heir" by primogeniture (as well as the given name) of Thomas & Martha (Savery) Perrin of Hebron, Connecticut.Rev. Daniel Perrin was too close in time to the people involved to have made that relationship up.
I wouldn't worry too much about the distinction between 1791 and 1793 on Thomas's birthdate.It was not uncommon for men as well as women to shave a few years off their age, or for their children to add years on to their aged parents.With a little luck, you might find a contemporaneous record in Springfield that will clarify this for you.Let us know if you make any progress.
By the way, I noted on familysearch that at least one submitter believes that Elizabeth's maiden name was Spencer.Do you give that any credence?The Connecticut Valley Spencers are very numerous, and the subject of considerable research.