Happy anniversary all around!
My first trip was July 12-19. My parents took the kids and grandkids to Aulani. There were 13 in our group total. We came in separate groups, since we live in different areas. DH, DD (5 at the time) and I had already booked Speedi Shuttle (as did the rest of my family due to enjoying the resort and not paying parking fees). Our plane was delayed a few hours. We got a private ride in an SUV to Aulani somehow with a Speedi Shuttle driver. The ride back was a shared shuttle. Both experiences were very positive. I didn't hear any complaints from my family regarding their service either.
We also booked a rental car through the Alamo desk on site. If you are a Costco member, make sure to check their rental car rates...and often. You should also check through
http://www.discounthawaiicarrental.com. Neither one of these cost to reserve, so you can always change your reservation if a cheaper rate becomes available.
Since you are going during a peak time, I highly suggest looking into reserving an Ama Ama deck, Executive Lanai or Cabana on days you plan to stay and enjoy the amenities. The EL and cabanas are a definite splurge. The upper Ama Ama deck is less than $100-you get 2 casabellas overlooking the lagoon, and really good service. It is nice to not have to stake out a place at 7 in the morning, and then risk having our stuff moved around.