I've learned over the years if you can't find someone and know they are there it is often an indexing error (by the indexer or because of an enumerator's spelling error). Only twice have I had someone really missed by the enumerator.
So looking at another version of the index (by another provider or an older printed format) or looking at the original census page by page is the solution usually.
PS If you look at familysearch, it has the early quebec/lower canada/canada east census and Joshua Hill is there back thru 1825 and what is possibly Peter's father John may be too.
Oh, and that seekingmichigan.org site has the surviving state census too. To get the proper search fields you have to fiddle. Under Advanced Search, in the right column uncheck death certs and check State Census 1884-1894. Then just click search with nothing else. Once the results appear, click on advanced search and now the fields will apply to the census instead of the death certs. For some reason it does not automatically switch the fields when you change what you want to search. Good Luck