"Steemit, Inc. should only delegate the SP, but of course not influence the decisions of the elected committee (elected by the community, not by Steemit, Inc.)."
I just don't think that's possible. I am unable to recall an example of folks providing funding without having influence on how it's spent, other than taxpayers, and that's because we're just extorted.
Nevertheless, that would be my suggestion (Steemit, Inc. contributes only the SP, and the community elects an independant committee).
If Steemit, Inc. would agree to doing that, is another question of course ... :)