1. Use the onkeypress JS method to get the pressed keyvalue in handler.
are you using the rendering engine as Motorola-webkit or Stock-webkit in android, which version of Rho are you using???
I feel, if the focus will go out of textbox then keypad will hide automatically if android Stock is the rendering engine.
2. Rho uses the native keyboard of android, as per my knowledge there is no rhoelements api available to change the Next' button to 'Go' button in Rho
3.There is no rho app to perform this, but all the available HTML/HTML5 input type must work because Rho uses the stock webkit as rendering engine.