Yamaha DTXpress/DTXplorer/DTXtreme

i am new to the dtxpress (it is just dtxpress, not II or III) and have a 
couple of questions:

a) will the module accept any electronic pad i purchase to add or replace 
an existing pad on my kit?
b) i would like to replace the ride with one that is capable of playing on 
the bell - will this require two inputs or can i simply input it into the 
ride input.
c) i have seen some sophisticated electronic hi hats (my current one is 
just a pad).  will these work on the dtxpress?