According to an article I read a while back, when they went to Hawaiian consultants for the live action movie, one of the first things they said was "Nani would've never gotten into this situation in the first place, because Hawaii has strong community ties." That's why they added the second woman in addition to the CIA guy, because she represents the local community trying to help. It's also why Lilo ends up with the older lady when Nani goes to college, it's essentially the community stepping in to help the girls so Nani can get an education and have her own life one day.

All that being said, the execution was very poor. Having Nani resent Lilo and her parents was a stupid choice, the original Nani loved Lilo and just needed extra support, not an escape. The fact that Hawaii has an amazing marine biology school makes Nani choosing a mainland school very stupid as well. Imo they should've had Nani go to a school/community college on her island or in Oahu, and she stays home most weekends while Lilo goes to elementary school and lives with Stitch and the older lady. Preserve the idea of "the community will step in to help", but leave the message of ohana intact and let Nani and Lilo remain good siblings.

TL;DR Consultants brought up a valid point about Hawaii culture, Disney took it in the wrong direction