Distributions of the median relative magnification factors and time delays obtained from EM observations for the source–lens galaxy systems within the localized sky area of each double-image case. The blue and green dashed lines indicate the constrained boundaries of μ_rel,GW and Δt_GW inferred from the observed lensed GW signals. Blue dots represent lensing systems consistent with the μ_rel,GW constraint, while gray dots denote the systems inconsistent with either constraint. Note that no systems are consistent with only the Δt_GW constraint because the GW time delays are tightly constrained. Magenta stars indicate systems consistent with both μ_rel,GW and Δt_GW. The inset highlights the error bars on μ_rel,EM and Δt_EM. For the lowest (highest) ρ_mean cases, five (one) systems remain consistent with the two GW observables.