Regarding flights--it is individual airlines who make cancellation decisions--the airports stay open until it is no longer safe to allow a plane to land or take off. With Charley outgoing flights stayed functioning the longest---while incoming flights and trains began cancelling that morning.
If you can afford to come in day earlier either money-wise or work-wise, that might be a good idea b/c if it doesn't hit, travel will still be messed up.
Disney tends to be sympathetic as is most of the travel industry, in times like this, but they are not obligated to be this way. If you haven't purchased
trip insurance, now would be a good time to get some and then your trip is fully refundable.
Disney resort is a safe place to be for a hurricane--but if we do have a hurricane warning--given landfall to be during daylight hours on Saturday, the theme parks will be closed--and within a couple of hours of immiment landfall and Orlando area impact, services such as food courts and such will close until the storm passes.
Best to call CRO for your particular situation to see what would happen if you cannot make it for some reason on your scheduled day. Again, they can still uphold cancellation policies--but the odds are that you will have no penalties, if the hurricane is imminent if you change your plans. Better to be pro-active about it than to wait until your travel day or after the fact.
Good luck--my hurricane preparedness starts today as we are at present the predicted landfall area for Francess (I live on a barrier island in the Melbourne area).