I recently switched devices and was required to make a new Apple ID account for this new device. I have successfully used family sharing to get all of my purchases back except one.
I am unable to restore my sound pack purchases. Before anyone asks yes I did purchase them and yes I do have the IF assistant app installed.
Just so happened I had just then taken off on a two week family vacation. :-) The “restore purchase” button sometimes has had issues. But all the in-apps are “one-time only” purchases, so if you simply try to purchase them again with the same(!) iTunes account it should say “you’ve already purchased this do you want to get it again for free?” You could try that.