I think there's a line to be drawn between buttons the Lord can press that require authority and those that merely maintain the administration.
Managing estates is not something that can be delegated. Period. That is part of the Lord's feudal duty to and authority over his vassal knights, and needs to remain something that only the Lord can do.
Controlling food distribution is merely a part of how the region is managed. It clearly falls into the same category as existing tasks the Steward can perform, and should be opened up to Stewards.
Others of these fall in the middle between these two; personally, off the top of my head, I would say that building infrastructure and holding courts both require the Lord's authority, while setting taxes probably falls just this side of the "administration" line.
I'm ambivalent about the militia ones.
