Since I use a different Mac as the base all the music in house from me(mostly) and my wife(few) I would have to sync using my Mac which does NOT have the song on it. It IS on my wife's Mac but if I sync with that it would wipe out all the songs(I have previously synced from MY Mac to it), right? SO, it appears, if I desire to KEEP using MY Mac as the main holder of music media that hosts the clients(wife's Mac mini, two iPhones), I must install the songs she wants on MY mac first and then sync her iPhone to it, correct? But. I don't want this stuff on my Mac or having to do that.
I DO like your 2nd option, if I understand correctly, please expand on how to do that.
Do you mean:
I can bring up the Music app on her Mac mini, connect her iphone via USB and then just drag and drop an individual song from the mini's song list onto . . . uh, what? on her iPhone?
This seems exactly what I want!