I don't have a lot of experience using laquer, but do have a chemistry background that would let me answer at least a portion of your question.
I think it's unlikely that Deft would work well in your mixture, as it's a CAB acrylic laquer rather than a nitrocellulose laquer, and I'd think it would have miscibility problems in alcohol (ethanol). Nitrocellulose laquer is no longer very common, since it yellows over time, and is dangerous to prepare (for the manufacturer, not the user). Because of the yellowing, most people choose a CAB acrylic laquer or a pre-catalyzed laquer over nitrocellulose.
I assume you mean "hardens faster" rather than "dries faster" in comparison with shellac. There are few finishes that dry faster than shellac-alcohol mixtures, which is almost instant. That's the chief drawback - it doesn't flow well because the ethanol evaporates so quickly that it leaves brush marks in place. But did you know that you can dissolve shellac in laquer thinner? Doing so considerably improves the flowability, particularly since you can add a retarder to the mixture to slow evaporation to your liking.
I've used laquer thinner to dissolve shellac in the past, and it does level much better, though it stinks to high heaven. I went back to alcohol for this very reason - a shellac/ethanol mixture is completely non-toxic unless you make it with denatured alcohol and then drink it. ;-)
It's been my experience that shellac freshly prepared from flakes in water-free denatured ethanol will harden enough to sand well after about 3 days in low humidity, and about a week in the high humidity of summer.
