Well, that does make it difficult. However, there are some things working in your favour - the first being that there weren't that many people living in BC in the 1940s. I think the population today is only around 4 million and that has probably doubled in the last 20 yrs. So the BC Directory actually includes the residents of most of the main towns in the province. The second is that there are two main corn growing areas around Vancouver - Richmond is now considered a suburb of Vancouver but when my grandparents lived there in the 1930s, it was entirely farmland. The second is Chilliwack in the Fraser Valley, about 80kms east of Vancouver. They honestly grow the best corn I have ever eaten! And lastly, most people emigrating to BC settled near the larger towns because most of our province (even today) is completely inaccessible. Mountains and trees everywhere!
So I don't mind having a look for a Lewis or two while I do other searches in the directories but I would need at least a first name to start with.