There'll be a point at which the Lehle will start blocking the signal until, by the time you're at DC, it won't pass anything. And actually, the DC on outputs thing with the 2600 goes back to the beginning, as ARP figured that if you wanted to use the 2600 for something of a complex modulation source, you'll need those to be DC-coupled. Smart...but a tad annoying.
Now, how that "stereo" crossfader gets used is interesting. One method is to use it to send a rather complex patch to either the left or right, this then leaves the opposite external output free for routing a lead line. You can also use the stereo out inputs in conjunction with the electronic switch, to create something that abruptly flicks from left to right and back. And so on...like pretty much the entire unit, there's stuff you can explore for weeks at a time and STILL only scratch the surface.