Goldenrivett
Although B+Y also has half elevator it doesn't appear to be that critical. Except AP is not available and landing gear is by gravity extension (since you don't want to risk the only hydraulics) most things are available and therefore in B+Y you remain in NORMAL LAW.Half elevator also has aileron like effect since it is on one side. With no ailerons this may be more difficult to handle in alternate law. Since both slats and flaps are available AC attitude is normal and ATHR control is satisfactory.