Intensity mapping opens up an exciting window for probing both astrophysics and cosmology during the Epoch of Reionization, with power and cross power spectra of line fluctuations testing models over a large range of scales and redshifts. We simulate cosmological volumes of 21-cm, Lyman-alpha and H-alpha line fluctuations and use their cross-correlations to probe properties of the IGM. The signal-to-noise of the cross-signal is predicted for SKA together with the proposed cosmic dawn intensity mapping (CDIM) satellite. In addition, these results for intensity mapping are compared to cross-correlation synergies of the 21-cm signal with surveys of Lyman-alpha emitters.