Others may not like that Nas listed his daughter in order for her to continue to receive money, but to me it is just a form of passing down his legacy like people do in wills. Everyone else might have worked on it, but it is HIS work in the end, and he can do with he what he wants.
If Nas had the authority and power to list his daughter as the executive producer, then is is fair to the others. The agreement with the other executive producers was separate from his agreement with Destiny. As long as he followed the terms of his contracts and employment with the other executive producers, it is only fair that he pass his income to his children as he wishes.
Yes, listing his daughter on his album as the executive producer is fair because it is his album. There is a good chance that he actually is the executive producer of the album because it does not make sense that someone else would have let him leave their name out.
No, this is not fair. Destiny should not be allowed to receive royalty checks from the album if she didn't actually do any work on the album itself. Nas should not have been able to list her as an executive producer. This is taking money away from those who actually worked on the album.