I just called them and he said they would stack. As long as the vacation package is booked directly through WDW and has the 8-digit code, the 0% interest should kick in automatically. Also, he said that there was a way to pay off your “non-package” charges and still keep the 0% interest on the vacation–
This is the scenario I asked him:
For instance if you charge $1500 on a vacation package, that should give you the 5% (or 6% for those lucky ducks) Disney Reward, anything over the $1500 limit (I don’t know if others got different limit amounts on this) would be the 1% rate. This entire charge amount would be eligible for the 0% interest for 6 months, since it’s a Disney vacation package.
Any other charges made (dining, whatever) would get the 1% reward rate, but would need to be paid off monthly as per normal. (Not eligible for the 0% financing)
If I paid off JUST these other charges plus whatever minimum on the vacation package, that would work. In other words, they wouldn’t apply the entire payment to the 0% vacation package first, leaving me to incur interest on non-0% purchases.
If you call Chase Disney CC, press “0” at some point to get to speak to a human. They kept wanting me to go to the app/website to “avoid waits” and once they gave me the “0” option there was not a wait at all- picked up right away by an agent.