The real answer to how the soft openings will work is, we don't know.
I was in HS while there were soft openings for Star Tours. It would be open for a while and then closed. You never knew what to expect. You could be in line and told the ride was closed and that you needed to leave. I would think rides could work like this.
Saying that, I would not think they would close off the entire area once they have it opened, but the rides may open or closed at any time.