How much side-to-side foot movement is possible in Crankbrothers clipless pedals?
I happen to use candy pedals so I measured how much I could move a shoe laterally on a pedal when clipped in - it's about 2mm.

However the pedal is holding the cleat quite tightly and and I'm pretty sure the cleat does not really 'float' laterally when riding. If the heel of the foot wants to move off the cleat centerline that is provided for by rotational float.