In case you didn't know, the last walkman releases require Android 4.2 or greater. It would be no surprise if the Z2 apps required at least Android 4.4
I've tried a bunch of ports on my mini pro, and none worked properly because of the unsupported resolution. Some guys told me to change the DPI density but meh, a music player isn't worth making the whole system look ugly IMO.
CyanogenMod-loving Xperia Mini Pro user.