We present lattice QCD calculations of higher order cumulants of electric charge distributions for small baryon chemical potentials $mu_B$ by using up to NNNLO Taylor expansions. Ratios of these cumulants are evaluated on the pseudo-critical line, $T_{pc}(mu_B)$, of the chiral transition and compared to corresponding measurements in heavy ion collision experiments by the STAR and PHENIX Collaborations. We demonstrate that these comparisons give strong constraints on freeze-out parameters. Furthermore, we use strangeness fluctuation observables to compute the ratio $mu_S/mu_B$ on the crossover line and compare it to $mu_S/mu_B$ at freeze-out stemming from fits to strange baryon yields measured by the STAR Collaboration.