I suspect the high faucet will cause splashing only because their little hands might be higher than the bowl when they wash. But the faucet wouldn't splash on it's own.

As for the shower bar, depends how much room you have and how you envision everyone using it. If it's centered, possibly all you might need, but you have to consider the height range of the bar and get it just right (max high and low levels). Or you can install a separate head above, install the bar underneath, and have no worries about the height meeting everyone's needs. BTW, if you install a diverter, make sure it is reachable for everyone.