Just a note here…
Way back when I got my iPhone 5 I took the appropriate kext files from iTunes 10.7 and placed them in the same place inside the iTunes 10.6.3 app.
Running 10.6.3 then and plugging in my iPhone 5 had no affect, I was still advised to update and the phone would not sync.
I am reasonably sure that this is because there is some sort of check to see if the connector is a lightning cable and if it's not then iTunes rejects syncing. Could be wrong on that, but in any case there is some checking somewhere as the 10.7 kext files do not allow syncing when used with 10.6.3.
https://forums.macrumors.com/threads/iphone-5-on-a-ppc.1443299/#post-15769910
^^^My post, the response and then my response are the ones to note.
Intel has said that there is enough in usbmuxd to allow the 5 to export photos to iPhoto (there was another thread on this) but not enough for syncing to iTunes.
If you can work around all that and get it to sync with a 5 or better that's awesome!