I cannot help but I think that this is a very interesting question

I do not believe that there exist rigorously derived relations between the shear viscosity, magnetic field and temperature in the quantum Hall regime (although they must be derived some day). [Notably, in the case of solid state systems one would call it shear modulus (http://en.wikipedia.org/wiki/Shear_modulus), rather than the share viscosity.] However, there should be research on such correlations for shear modulus obtained empirically from real or computer experiments (molecular dynamics). A thoughtful literature search would help. Some references can be found on Wiki.