In my games, any spirit can perform physical tasks or use its powers on your behalf, but when you ask a spirit to support your magic (i.e., aid sorcery, aid study, spell sustaining, spell binding), it must be a spirit of the correct type according to your tradition.
As Reaver points out, SR5 is a little vague on this point, but previous editions were clear enough, and the intent remains the same. SR4A p.187: "The magical services available from a bound spirit are Aid Sorcery, Aid Study, Spell Sustaining, and Spell Binding. A spirit intended to assist the magician with magic must match the category of magic according to the magician's tradition."