I think a June reservation may always be harder to get, no matter what the year. I think mid to late June, coinciding with the week "school's out" is a popular time for families of school-age children to book. Knowing this, we purposely picked a week in July that worked for my teen and tween schedules (althletics, summer theater, etc.) and had no problem getting a 2BR. I got my second choice on view (island gardens) but was really grateful I got my dates and size.
I think August dates may be even easier to get as most colleges and schools in the South return well before Labor Day.
But, eventually, I agree that Aulani may be a very high demand booking. Although the resort will be big, once it is sold out to Aulani owners, I think ressies will be difficult for anyone that doesn't own.