A:Answer Speaking from experience with previous games here: You should be fine. :)
Best Buy's system won't allow orders for stock that isn't accounted for. In fact, a surplus number must always available in their system to account for replacements (in case initial stock/ordered stock is damaged). However, they are marked unavailable until they are no longer needed. All of these are applicable reasons for orders opening back up (however brief):
1) Best Buy secured additional stock for launch
2) Someone cancelled their pre-order
3) Someone's card was declined or expired, automatically cancelling their pre-order
4) Back-up (replacement) stock was no longer necessary, and thus released for standard order/pre-order
I've secured more than a couple collector's editions via pre-orders that were available after the initial order period was closed on the Best Buy website, then briefly re-opened for the various reasons above. I also had a success day-of launch for The Legend of Zelda: Breath of the Wild Master Edition by going into the store and securing one of their backup "no longer needed" replacement surplus. It's not uncommon you'll see an on/off influx of the pre-order being available again for brief spurts around launch as a result of people's cards being declined (this is on their side, not Best Buy's - so if you have a valid card, there's no need to worry).
Hopefully this helps alleviate some of your concerns.
