I take it that aid to impoverished orphans also might run afoul of nondiscrimination as Buchanan understands the term. If so—if this is even a close question or a plausible reading of the Buchanan idea—then I think this proposal needs to go back to the drawing board for careful rethinking and redrafting.
If Buchanan's generality requirement rules out government-disbursed aid to poor orphans, is it thereby reduced to absurdity? Is that a deal killer? Does Buchanan need to stay at the drawing board until he is no longer libertarian? Anyway, Buchanan does allow for old-age insurance under the generality requirement. So it may be that “social insurance” programs designed to secure people against the event of falling into poverty, including programs for poor orphans, may generally pass muster in terms of non-discrimination.