Moving iTunes from one PC to three MacBook Pros - how?

We started using Mac products because of the iPod. Each of our three family members in the household (dad, mom, and daughter) each created an iTunes account when we started; one for each iPod, however, we used dad’s Apple ID as the “master” account for iTunes. Anytime we purchased music we added it to the iTunes library using dad’s Apple ID. Back then, we were PC users and the PC held our iTunes library so it wasn’t a problem because we could each download music on to our own iPods from the master library with no problem. Today, all three of us have MacBook Pros and all have iPhones too.

Because we all each have our own Macs and we each have our “own” music we listen to from the master iTunes library account (dad’s) on our phones and iPods, how can we permanently move the music (and everything else like apps, pictures, etc.) on to each of our own MacBook Pros, yet still share the music (and stuff) with each other when we buy new music? The PC is dying and we have transitioned to each having our own Macs, yet we still want to share the music and stuff with each other when we buy new music or apps like before, yet we are not going to have a “master” iTunes library in a central computer? When we updated our iPhones, we used the master iTunes library.

I know we can use Home Share in iTunes to share music but it is my understanding that you have to use the same Apple ID (account) on all shared computes and devices to stream music using the same Wi-Fi network.

We can transfer all the music from the master library on the PC using Home Sharing to our own iTunes library on the Macs – not a problem. Do I need to actually copy the iTunes Music Folder files too to the Macs or just transfer music with Home Sharing?

Problem:

When mom or daughter each tries to updates their phones will the iTunes library on their Macs be overridden when they try to update their iPhones using their own Apple ID in iTunes? Will they lose all their music (and stuff) on their machines to be overridden by their iPhone?

I know we may have initially set up the accounts incorrectly when we first started by having a master library but we didn’t know what we were doing (not like we have improved much since then, but that’s another conversation) and we definitely did not anticipate or foresee each of us owning our own MacBook Pros.

Is there a way we can make the transition without being penalized for being shortsighted when we started this several years ago? Any assistance would be appreciated.

Thanks!