I may be able to help as I have quite a few census resources from 1790-1920. Just post the specific names, approximate years wanted and I will see what I can find. As you know, it all depends when a town was incorporated as to what the census designation will be. You are likely looking at T17 or 18, R5-9, Wallagrass Plantation, Frenchville, etc. before 1900. I did not fine any mention of Ouellette before 1900. There is a good description of the area in "History of Aroostook" and your relative's names may even be in there. So. . . just give me some details and maybe we'll find the right place.
Regards, Sharyn Hay storknurse