E07K wiring options might not allow for both headphones and the line-out adapter for the active speakers to be simultaneously connected. The adapter goes into the dock connector which is right next to the earphone output. D-Zero would probably allow both 3.5mm plugs to be in there simultaneously, and just require pulling out the headphone if you're using the speakers, but think carefully about how this will go on your desk because it looks messy. You can't use an angled plug on the speaker's because that will block the volume knob, and it might be difficult to use if it's facing away from you. Wire management looks real messy with it still (I used mine with just active speakers, so it faced away from me, and I used a short Monoprice USB cable out the side of my laptop).
E10 has a lineout at the rear and a headphone output in front, but a USB-powered headphone amp+DAC isn't likely to be more powerful than wherever your headphones are plugged into right now. Also, like the other two, all it will have is a lineout, not a preamp output, so if you have to change the volume on your speakers, you'd still have to reach over to the speaker cabinet.
Search for "audio interface" here and you're going to see all sorts of threads looking for a device that can do all these properly and with better wire management. I think the cheapest is around $120, but I'm not sure how powerful the headphone amp on that is and if that might be enough for you. For a less professional-oriented product, something like the AudioGD NFB12 or NFB11 would work.