This is different to MJ case I believe. Amy has almost finished recording the album. She even wanted to set a release date long time ago. And they, including her dad, now have to choose which song to put on the album so I think shes done a lot already. This album will have a 1M debut.
She told me it was her first time in a studio in over a year, and she was quite obviously nervous, fiddling with her hair, shuffling her feet - but when she sang ... boy. Watching the old veteran and young ingenue together was extraordinary.
Why would releasing her music be disrespectful to her memory? What it would really do is give people MORE to remember her by. It's how they handle the release that could disrespect her, but we'll have to see how that turns out.
A source tells The People, “She has finally finished the album and it’s ready to go. They were just about to finalise a release date and then this happened. She is back in rehab for the foreseeable future so it is just a question of waiting and seeing now. But there is no way they can give a specific release date until they know she is likely to be out.”
They moved quick to promote her stuff on iTunes after her death, I wouldn't be surprised at a whole "album" of unfinished material to come out.
EDIT: At the same time, it was said she was going to release the album in January this year. So I really doubt all she had were demos. Something was ready to come out, Amy just wasn't ready personally. We'll see though.