The AMT103-V comes with a kit with many different size shaft adapters. The snow colored one (I assume they mean white) will fit the 1/4" shaft of the nano gearbox.
The mounting pattern is not the same as the E4P encoders so you will have to figure something out. Either drill small pilot holes and use plastite screw to fasten it down to the pad or use strong 2 sided tape (3M VHB). You may want to fab an alignment bushing to do this to ensure proper alignment, although if you are careful you should be able to skip this step.
I am not sure whether or not it comes with a cable, but I would doubt it. We were planning on ordering these using our $50 FIRST Digikey credit.
http://www.digikey.com/product-searc...?k=102-1504-ND