Toomre diagram for all stars in (1 − 3)R_d (R_d is the disc scale-length) and |z|> 2 kpc (first row), in situ stars (second row), and all accreted populations (third row). The mass fraction of in situ and accreted populations are shown at the bottom in the second and third rows, respectively. The five rows below the gap correspond to the Toomre diagram for five of the most significant mergers at z = 0 (M1–M5; see Fig. 4 in Paper I). The merger accretion lookback time (Gyr), total stellar mass of the merger debris at the time of the merger (log₁₀(M_*/M_⊙)), and the stellar mass ratio (μ_*) relative to the main M31/MW progenitor at the time of the merger are given in the bottom left corner of each panel. The colour bar is in M_* scale. The white circle corresponds to the thick disc selection: V_circ180(km s⁻¹)/240(km s⁻¹), where V_circ is the circular velocity value at 2R_d for each galaxy; 180 km s⁻¹ corresponds to the selection made for the MW; and 240 km s⁻¹ is the MW circular velocity. We suggest that the disc-like regions in the Toomre diagram are populated by the accreted stars. A single debris spans over a large volume, and, in some cases, the bulk of the accreted stars have (thick) disc-like kinematics.