You will completely LOVE Aulani! My family and I have been twice in the past 2 years and both trips were very memorable and as always - magical! We travelled in Feb last year and April this year staying in a Studio room. Aunties Beach House was an amazing experience for our kids! The first year we went our youngest was 2, so was unable to be left during regular hours there. We could, however go as a family during their 'open house' times in the morning (check your 'Daily Iwa' for the schedule). Our older child could be dropped off and enjoyed many of the programs and open play times that they offered. This year both kids were old enough to be dropped off! They took part in lots of the programs - but their favourite by far was 'Stitches Space Goo'. A MUST for your kids! As with most things Disney - some planning is involved. But, I always found our Aulani planning to be a great part of our day! In the evening we would wander to the lobby and get the next days 'Daily Iwa' - in that you will find a list of the programs for the next day at Auntie's, as well as the rest of the hotels event schedule for the next day. I would also check at the same time what the attendance is like at the hotel. If it is high then you will want to go early (max 1/2 hour before opening) to line up for a spot in some of the more popular programs (like Stitch). For the free play we have NEVER had any problem getting the kids in. There was always room. Another note: If you want your kids to be there for lunch or dinner - you will want to order that early in the day to ensure room. Our trips were both during off-season, so we never encountered any large crowds or difficulty with getting into programs. Your kids will love it!!
Aluani is a magical place. Enjoy your trip! Make sure you see the Starlit Hui and enjoy the movie nights on the lawn! Disney really has done an amazing job with this hotel - my only complaint about it would be that it is not Disney enough for me! But ... it certainly is beautiful, clean, fun and safe. I loved every moment my family was there - I hope you do too!
One more thing: We enjoyed the character breakfast both years! Food was good (standard breakfast fare at a buffet) and the entertainment for the kids was great!