Haunted Mansion goes down in september, I believe, because it gets the NBC layover for the Halloween season as well. I don't know about IASW though, but i'm sure someone here will.
Haunted Mansion close in the last week of August to reopen by September 14th for the Halloween Season. This is when it gets its Holiday Haunted Mansion overlay for Halloween and the Holidays. It stays until open until right after the Holidays which will probably be January 6th.
It's a Small World close the 4th week of October probably on the 21st or 23rd to receive its layover. It takes about 3 weeks to install and reopened near when the Holiday start. It may reopen on November 9th. It keeps this overlay and closes after the Haunted Mansion reopens in January around Presidents Day Weeekend.