It seems one really only has two options: creating a point feature class and projecting it, or using ConvertCoordinateNotation, which allows you to skip making the original input featureclass, but requires you to make an input table.
Thus, you don't just need an input FILE, you need an input TABLE.
(AML had a handy option for projecting coordinates in a text file... but enough nostalgia for today.)
ConvertCoordinateNotation also generates fields for the output coordinate values, so it skips needing AddXY after just projecting a feature class.