As mentioned by T. Kerwin, the 1940 census is not yet transcribed and indexed (thus it is not yet a searchable database).
However, you can look at the 1940 census page by page. Go to Ancestry.com. Choose to look at the 1940 census. (This is available for free for the time being.) Choose Michigan. Choose Kalamazoo County. Then choose Schoolcraft township.
Would take a little time to scroll through page by page, but certainly doable. Of course there's no guarantee the people you seek are there in 1940.