from my faraway viewpoint of your dilemma, it looks like one of the main issues would be, you do not play yourself. are your kids already taking lessons ? if their teacher has a good instrument (s)he might be a good resource to bring to look at the pianos. or bring some other serious player of your acquaintance with you, which would not tell you how the pianos feel differently (depending how articulate your acquaintance is of course), but might reveal more about how they respond. response at the softest ppp level of volume is very important, and not always revealed by a piano salesperson demonstrating the instrument.
with the highest quality uprights, the 'tall footprint' that you expressed concern over is a positive factor because string length and thickness matter. you are the only one who can decide how much a difference the finish makes. for most people who enjoy playing and studying piano, it often is one of the less important factors. if the schimmel is only a bit more expensive than the taller yamaha, it probably represents a better buy for the $$. you are probably not in western/central Europe, because yamahas usually go for lower prices there, facing stiff competition in the market with European made instruments. that schimmel upright to a large degree is made for European buyers who want to approach a small grand's sound and response in an upright piano. my guess, the pianos make a very different sound impression on you (yamahas to me have a different 'soundprint' than the european) ; maybe ask yourself, which would you prefer to hear for hundreds of hours over the years.