Lower left pic: That appears to be a different bike, a 4-wheeler, with trailing arm rear suspension. Interesting!

The front suspension, with parallel equal length A-arms (I see the top arms are a bit shorter for kingpin inclination to put the steering axis at tire contact center, so a bit of camber change gain, but we will assume equal length): The instant center for the arms is at infinity, so theoretical infinite length swing arm, so the steering knuckle and wheel moves up and down with no camber change. If the arms are parallel with the ground, this puts the roll center at ground level. This is low, so a normal vehicle would have a lot of outside body lean in cornering due to the long moment arm between the center of gravity and the roll center. HOWEVER, with the bike leaning into turns, this is not a factor! Same for the 4-wheeler on trailing arms, at static (not turning), roll center at ground level, and that would change with the bike turning, but again, with the bike leaning into turns, the roll center height has little effect.

These are very interesting bikes. I'm reading now that your bikes are also termed as "bakfiets" (Dutch for "box bike") , same as the long wheelbase "long john" front cargo bikes (I couldn't remember this term earlier), but with 3 or 4 wheels, yours may be more stable at low speed with heavy loads.