I am not an expert with holding tickets on the MDE account, but I know you can have multiple tickets assigned to one person with no problem. I also have an AP, and have an additional 6 day park hopper ticket currently attached to myself. I have reassigned it between my sister and I numerous time with a simple click and confirmation.
From what I have read, the problem could arise when entering the park if the AP is somehow not the primary admission and you use a day of your new 7 day hopper ticket instead of your AP. The ticket would then be activated and expire within 14 days. I acquired this 6 day ticket AFTER going to the parks, and I will definitely make sure it is on a placeholder before I use my AP again. The placeholders are an easy way to ensure the extra tickets are not able to be accessed by your band upon entry. If it is attached to a placeholder, you would just log into MDE, and reassign it back to yourself. As long as you manage the placeholder and it is not a relative or friend with his/her MDE own account, you can take the ticket back no problem.