Hey, If you're on XBOX and you're the one who purchased the pre-order content, go to the Manage Game menu for Destiny 2. Go into the add-ons and install all the add-ons for the game. If the pre-order bonuses are already installed, uninstall and reinstall them. Afterwards, restart Destiny 2, and then go to Rahool in the tower to look for your pre-order bonuses. If you're the one who did the pre-order, the gameshare shouldn't matter because you're the actual owner of the licenses. If your friend did the pre-order, the bonuses should go to them. Getting pre-order bonuses has been very iffy on XBOX, and the solution I listed is the best working one out there.

Hey there! While you are able to use Xbox’s game sharing feature, Bungie does not fully support it. [quote]* Players accessing Destiny content through the game sharing feature may not be able to access all DLC, add-ons, promotional items, or pre-order items for which the primary account owns the licenses. * Bungie does not support any issues with loss of access to items on accounts that are using the game sharing features to access Destiny content.[/quote] https://www.bungie.net/en/Help/Article/12458

I share with my son and he has always received the bonuses when it comes to Destiny, but that is not always the case. I preorder the digital deluxe of Avengers and he isn’t able to access any or the bonuses.

I don't believe so. It's whoever purchases the expansion that typically gets the bonus. Although I believe weapons and quests are still given, but not like...cosmetics I don't think.

Since the Beyond Light pre order bonus counts as a DLC it should share it with your friend!