Distribution of λ parameter and triaxiality in the stellar halos (i.e. at R ≥ 4 R_e) for different intrinsic shapes in the central regions, parametrized by the intermediate to major axis ratio p(1 R_e). TNG100 and TNG50 galaxies are shown separately, in the top and bottom panels respectively. These distributions are not systematically dependent on p(1 R_e), and thus the stellar halo spin and triaxiality remain unbiased after implementing a sample selection based on p(1 R_e).