Several areas in Agincourt are “detailed” in maps of this sort. They tended to grow organically and may not actually represent that neighborhood at a single point in time. Cities are like the palimpsest of the Middle Ages: a sheep skin inscribed with message after message, each scraped away to use it for another.
The texture of the city is set in its townsite plan, the pattern of streets and alleys, the grain of lot sizes and orientation. You can see it here: east-west running commercial lots (25 by 140 feet) would be far easier to sell than those running north-south. Why, you ask? Come visit Fargo some time and chart the vacancy rate for commercial space that faces north: I’ll bet they have a far higher turnover rate and command lower rents than those lots facing virtually any other direction. So Broad Streets commercial lots avoid a northerly orientation. In fact, so do most of the residential blocks — though there are exceptions in the T-blocks related to school sites.
The three 25-foot lots at the northeast corner were typical two-story late Victorian store fronts: shops with an upper floor of rental offices for the professions (law, medicine, dentistry, etc.). There is no guarantee of uniformity in floor heights or architectural details. So as the de Bijenkorf foothold at the corner allowed them to acquire adjacent stores as their business grew. By 1920 they occupied about 18,000 square feet on two floors — allowing a rectangular light well at the center for stairs and just a hint of big-city style.
Variations in second floor levels can be accommodated with stairs and ramps — a freight elevator is likely, but not one for passengers, I suspect (though I’ve drawn one here). But then there is the matter of harmonizing the disparate brick façades. That’s why the prosperous 20s are a good bet for this renovation: #1) strong economic conditions and #2) snazzy terracotta units to clad the exterior with Art Deco style. That is also why I was so happy to run into the Delmar–DeBaliviere Building in St Louis and its remarkable adaptation of Frank Lloyd Wright’s “textile block” houses in Southern California. Isadore Shank was a figure unfamiliar to me but I think he’s given me “an out.”
And you can also see why stylistic connections with the Netherlands are very likely.