Yeah, I’ve got experience with ducts. They won’t make sense for this application. In order for ducts to add efficiency, you need tight tolerances on the separation between the prop and the duct. The shape of the duct also matters a lot. So it’s pretty hard to do.
Now, let’s say you managed to deal with the above, using a duct wrecks your portability, and also adds a bit of cross sectional drag.
So, overall, I don’t think they’re appropriate for this design.
Now if you’re talking EDFs - like ones that spin at ~100,000 RPM, they’re even LESS appropriate for this purpose 
and have no efficiency at low airspeeds. They’re designed for high airspeed applications.