I think you first need to definitively choose which tyres you want to use. I would run 28 mm tyres on the Mavic Open Elite (but some brake quick-releases do not open enough to let the wheel out without partially deflating the tyre, especially if you like your brakes to come on early in the lever stroke). But 32 mm would be a step too far. It’s beyond Mavic’s recommendation too.
For 32 mm tyres you might consider the Exal LX17, unless it’s too heavy for your tastes?
On that topic: if, as is usually the case for some reason, wheel weights are considered without skewers, you arrive at about 1.9 kg with heavy (i.e. good) Shimano hubs, 36 spokes front and rear, brass nipples, and 450 g rims. Or 2.0 kg with that lot and 500 g rims. So your goal is reasonable.
A spoke weighs about 3 g and a brass nipple about 1 g, so using 32-spoke wheels front and rear knocks a packet of Polo mints off the whole bicycle weight (compared to 36-spoke wheels). This isn’t something that can be felt or translated to a measurable speed difference.
And that’s assuming the same rim weight, but paradoxically more spokes allow you to run a lighter rim that, since it cuts weight from the periphery, might make the wheel feel a touch lighter. Might!
I like plenty of spokes, but even if you don’t, the rim is a likelier place than the spokes to save weight and feel it.
Don’t forget the tyres and tubes! Light ones save more weight than you can easily save on wheels, and far more importantly, carefully chosen light tyres will have vastly lower rolling resistance than your Delta Cruiser Plus tyres.
