  We study impurity bound states and impurity-induced order in the
superconducting state of LiFeAs within a realistic five-band model based on the
band structure and impurity potentials obtained from density functional theory
(DFT). In agreement with recent experiments, we find that Co impurities are too
weak produce sub-gap bound states, whereas stronger impurities like Cu do. We
also obtain the bound state spectrum for magnetic impurities, such as Mn, and
show how spin-resolved tunnelling may determine the nature of the various
defect sites in iron pnictides, a prerequisite for using impurity bound states
as a probe of the ground state pairing symmetry. Lastly we show how impurities
pin both orbital and magnetic order, providing an explanation for a growing set
of experimental evidence for unusual magnetic phases in doped iron pnictides.
