(1) The Oregon State Archives historical births database
(2) The 1900 census
Helena Toews and Abram Esau had children starting in 1890 and ending in 1907. The book convinced me they would be gone by the 1910 census, and while the parents might have been in Polk for the 1890 census, that census is Gone (a fact which regularly irritates me). In the event, I have found the Esau family back in Manitoba (interestingly, they do not seem to have gone straight to Alberta, if, indeed, they _ever_ went to Alberta) in time for the 1901 census (not unexpected) where an immigration year for the US born children is given as ... 1899. Altho it's hard to get too depressed about a census that includes _full birth dates_ for everyone in the family.
Thus leaving me with option (1) above. I found two of the many children in the historical births database, both listed as "delayed births". I finally looked up what that meant.
In marginally better (altho if you think about it at all, really depressing) news, I am finding the kids who died relatively young in the Manitoba Vital Records database. Death records from 70 and more years ago are available in that database, so that may continue to work for ones who died in middle age as well. If they died in Manitoba. This is a nice, high quality source, however, it does not help in answering the larger question: are these actually Holdemans or not?