> Definitely seems like my first assumption was correct and there is no harm in putting your minimum group size at 1.
I suggest you call tomorrow (the 15th). If you get an answer on the phone and it turns out your assumption is wrong, you still have tomorrow to cancel and redo your lottery entries.
My $.02: that language doesn't disambiguate the method of selection. You're interpreting it to mean one thing, but it could just as easily mean "reconsidered for that date, prior to moving to the next date in the list". To me that is still the more logical method, but I really have no idea.