I really don't need the features offered with Apple's Family Sharing program, plus I don't want to get everything onto the iCloud (required) because her apps alone would surpass the 5GB free memory limit by many times, and I don't need more monthly payments (I have hard drives for that).

All I really want to do is, Sync her iPad to her computer instead of mine, and have her computer use the same Apple ID as mine, entitling her to use everything purchased on that account, but be able to manage her own device. I know this works with the App Store between computers, but does it work with iTunes and devices? And how would I get the library/apps over to her computer without having to re-download everything? Copy my library over to hers? Or just sync the iPad to her computer and it does a backup?
Thanks in advance!