With your updates, ios7 still has an issue mounting.. possibly libimobiledevice 1.1.6 solves the issue.
ios 4.2.1 appears to mount but gtkpod no longer works so cannot test
with this downgrade I am able to mount iso 4.2.1, use gtkpod to create playlist and sync and unmount as root in terminal.
with this downgrade ios7 has the same trust/password issue as prior and after
I forgot the defaults so guessed when down grading..prior to upgrade I think gtkpod was problematic because as user I could not mount. I had installed all the files but was expecting gtkpod to do all the work in user account.
To get playlist on ios 4.2.1 I added above files, created folder /media/ipod, in terminal su to root then type ifuse /media/ipod, then type gtkpod and use app then close and in terminal type umount /media/ipod
with ios7 I type ifuse /media/ipod but get error to remove password on phone and popup on phone trust this computer as mentioned in the link. they suggest libimobiledevice 1.1.6. I am not sure of the details of implimentation at the moment