You might see little uptick on the first two days since they are on the weekend and would be most popular with local Passholders who work during the week and come out and make a day of it. Beyond that, since it's likely only a few thousand people per window it's not likely to have all that much of an impact on the crowds at DHS.
Many schools will have started by that time, including Orange County. Will locals come that weekend? Maybe. But many probably have Gold passes and wouldn't have been eligible for the preview, so why visit then?