apple: Making Family Sharing work requires patience
OK, this is one of the most confusing things about the Family Sharing feature and the App Store. What I thought should happen is that if you are in a Family Sharing group, you should use see applications like Final Cut Pro appear as downloadable, but this is now how it works.
You need to make sure that the main head of household has enabled everything and that everyone is sharing. You also have to check in the App Store at the very bottom of the application that it supports Family Sharing. The Apple Pro apps do.
On the Mac App Store, you have to start it, click on the icon on the lower left which has your face on it, then in the menu, you will see a list of items you have purchased. But, at the upper right, there is a pull-down that is nearly invisible called "Purchased By", this should have a list, but at least for me, it did not populate for an hour or so, so you have to wait for a bit.