Hello Laytonlily.
I believe that you were given info about Thomas' marriage in this thread. Did you contact the church to inquire about the records?
http://www.rootschat.com/forum/index.php?topic=671182.msg5181137#msg5181137Here is info about the records from familysearch. You should, presumably, be able to obtain what you are looking for from the Ontario Genealogy Society mentioned therein. They should have info about any witnesses, who may be other family members.
https://familysearch.org/search/catalog/1184686?availability=Family%20History%20LibraryIt appears that the original film is not in circulation (click on number for for further info) but it is my understanding that you can order copies of records through familysearch. There is a thread about this on RootsChat somewhere.
If John married at St James, you should find his marriage in the records at this link.
http://homepages.rootsweb.ancestry.com/~maryc/old5.htmYou should be able to search through other available early parish records in the same website. There are not very many available on line, however.
Civil registration only began in Ontario in 1869 so your only recourse is to find a parish record of an event. Marriages are, however, more readily available from about 1858, I believe, but this would be later than the time you are looking at.
PB