If you are right with your findings, then the ZX1 is far superior to the ZX2(what I don't think). My well burned ZX1 is far superior to my A15, that is a fact for me. What kind of music is your preference btw.?
Funny enough, the ZX1 battery life is much better, even though the battery size is the same as is the OS running on the devices. Seems that Sony updated the ZX1 firmware better. The idle consumption is far less compared to the F886.
I heard that combo some weeks ago with my Z7. I and 2 friends found it far to bassy with the Z7, more suited for the HD650 or the AKG K702. I use a 7 years old Meier Audio Opera DAC/AMP and that is just fine, very powerfull and more neutral. I don't think that the Z7 needs a bass boost. Meier Audio has some recent offerings that are very interesting.
If you want to keep the Zune, and wanna go Schiit you could try out the Asgard2 fed by either the Zune or the Zx line out. The Zx DAC is not bad at all. And for gaming or movies you can use the SBX software which is quite good in simulating surround on headphones.