We use 4 wireless Sennheiser IEM systems, 2 wireless Shure mics, 1 wireless (Sennheiser) bass, 1 wireless guitar (Shure GLXD14R)
Also 6 wireless IPADs and wireless FOH mixing (Swissonic router)
If possible don't operate on 2.4 GHz, but on the 5 GHz band.
No issues at all.