If you have many instances of the same sprite, you can pick it via its UID or you can make an instance variable and set that when the object is created to a unique number. You can use this instance variable as a picking condition
You can detect keyboard buttons by using the keyboard object in your project, and creating a condition using the keyboard object "is key being pressed". You can assign instance variables to your text boxes as well, to give them a unique identifier - the same way as the sprites. You could even match the unique variable between the sprite and the text box (which is what I assume you're wanting to do).
You don't need families for this to work