Hi there Steve, and welcome to the forum.
do these program in C++ or C
C++ is the language used by the IDE.
I hope you enjoy playing with your Arduino. Certainly having a couple around is helpful for testing sending/receiving and so on.
You may want to consider making paragraphs in your future posts, makes them easier to read.
I'm not sure about the Android questions, maybe someone else can help you with that.
The Arduino Uno is sort-of the "default" Arduino, and a good place to get started. You can work your way through some of the tutorials and get familiar with using it, and the IDE.