I think the Dutch one has a kickstand?
Actually, if you were going to do the two-seats thing, you would want a really good kickstand. That might help. I found getting the kids in and out really tricky, tbh. (I did only do it once ... um ... and I had a crash with a car when I did it, which probably colours my experience. I don't think the crash had much to do with the two-seat arrangement, although the fact the other child on the back was screaming didn't help ... the crash was really the driver's fault, as he was making a right turn through me without signalling. Worth noting: neither child had a mark on them.)
With one child in a seat, you rest the bike against your hip, you plonk the kid in, you grab the handlebars, all ok. With two kids in seats, I'm not really sure what you do, you have to lean it against something other than your hip.
The weirdo bikes have the kids low down, so their centre of gravity is lower, so they're less likely to topple you.