I'm sure the more experienced will chime in here, but I'm going the same night and have decided to not get the EP. I think it depends on how much you want to ensure you see all seven houses - if you do, get the pass.
Some things to consider: the weather, it's Sunday, but it is Columbus day weekend, a lot of people have Monday off so might decide to go, it's still fairly early in the schedule, and is this the only night you're going?
Our group is going only this night, and we'd
like to see all houses, but won't be upset if we don't. Plus, the weather has been so crazy in Florida lately, if it rains we might not go at all (we do have park tickets but have not yet purchased our
HHN tickets).