Is the size of the series indicative of the number of cars originally purchased? For example, were there 527 cars in this series in 1909 (or whenever they got them from the Wisconsin Central)?
No. Earlier ORERs show 1,000 cars in the 108000-108999 series. Many RRs, when only a few cars were left in a number series, showed only the lowest and highest numbers of the cars remaining, and that's obviously what happened in this case.
