We have 3 Xbox Live accounts on our Xbox One. Mine is the main one since I am the adult, so any purchases made via console fall under my account. However, my boys have money on their accounts, so sometimes I'll make a purchase online via their account. The expansion pass was probably ordered on my account, but either of the boys probably downloaded the DLCs once they became available. But it's impossible for me to know who did what since the purchase of the expansion pack does not show up in any of our purchase histories.
In any case, once the Taken King digital download was made available for pre-order, my boys started to try to get it. It has always said "unavailable" on the console and "not available" online no matter whose Xbox Live account we were signed in on. Trying to buy it in-game doesn't work either.
Had we known ahead of time that all DLCs had to be purchased and downloaded under the same account, we would have.
How can my boys get the Taken King digital download for $39.99? How can they get the pre-order items?