1 Yes they will. The kings springs lower your car around 30mm. This will be quite suitable for your intended application & will firmin your ride slightly.
The Koni Reds are the single acting, one way adjustable damper & are excellent in road cars.
Cheap bastards option: if you have the original factory oil inserts, you can drain the oil out & replace it with heavier fork oil or ATF – works VERY well!
2 I lowered my bus with the lowered Kings springs – I am not sure what the rate is but the coil wire was 0.5 thicker than standard.
Perhaps speak to a Kings tech to clarify the rate. I highly doubt the ride quality will degrade much.
3 I only bottom out when I inadvertently drive through pot holes. You'd have to lower your Zed a loooooooong way for it to bottom out over normal tarmac surfaces.
4 In a road car? I doubt it. Koni (IMHO) is the superior brand but it all comes down to personal preference & depth of wallet.
5 Adjustable swaybars in a road car isn't necessary, they are only usefull for tuning your suspension for track use.
Non-adjustable bars, as long as they are uprated ones, will provide much more control over body roll than std ones without an increase in ride harshness.
Did that help Stevo?