We will be in Orlando September 27 - October 1. When will Universal start preparing for HHN, and will there be any attractions or areas of the parks that will be closed that week?
HHN opens the 2nd, so you may see some goings-on in the parks on the 1st, but nothing major.
Based on the HHN website, there *may* be a haunted house in or near earthquake. As you get closer to your trip, you may be able to call & see what, if anything, will be closed due to HHN.
The only house I can see effecting the park during the day would be Earthquake. The others appear to be in sound stages or buildings not used during the day.