Need help implementing a S1 project to S2

Hello:

Well, I´m still reviewing the Xbee manual (series 1) and comparing it with the Znet 2,5 (series 2) manual, actually I´m comparing three manuals including Xbee ZB manual.

Reading the Pin Signals section, I saw that PIN 14 for series1 and ZB are Vref (well in ZB Digi write a note about it) and in Series2 this pin must be not connected…in order to make a general board that allows me to interchange all three modules or at least series2 and ZBs what should I do with this PIN 14?, if I can have a Vref for ADC ZNets modules that will allow me to have greater voltage inputs at ADC terminal (remember that input voltage for ADC is 1,2V).
In ZB module manual said “A sample set consisting of 1 sample for each enabled ADC and/or DIO channel,
which has voltage inputs of 1143.75 and 342.1875mV.” and then follows “The analog reading is scaled such that 0x0000
represents 0V, and 0x3FF = 1.2V. (The analog inputs on the module cannot read more than
1.2V.)”, so which is the real input range for the ZB modules?, can I use a Vref to improve this input analog range at ADCs PINS (just like in series 1)?.

Another thing that I noticed is that Series1 has some commands that allows user to use more the ADC/DIO ports, including PWM that series 2 doesn´t (just for RSSI), for example the IO line passing is something cool, it exists a substitution of this behavior for ZNet 2,5 or ZB firmwares?, if exists how can I do it? if doesn´t why Digi exclude this kind of things for series upper than series 1?

I make this kind of question because, I´m going to buy more modules in order to make a greater project that the one I just finish. So I need to choose well which module offer me and adjust better to my requirements