If you use the Target Debit Card regularly (and have been a cardholder for awhile), you may not have a problem with limits, etc.
However, if you don't use the card regularly, or if you are applying for it for the sole purpose of buying the Disney cards with it, you may run-into some problems.
Also, be aware that your current checking account balance has no "real time" effect on the "swipe" you perform at the register, since the REDCard transaction is processed via the Automated Clearing House (ACH) and will hit your bank about 1 to 3 days after the swipe.
Best advice for those who have held the card and used it is to make a few trips spread-out over 3 or 4 days and buy about $400-$500 worth of cards at a time.