Flying leads is an expression that means that a prototype is wired together with a crazy bunch of individual wires.

For specifications of various LCD displays check out the web site of Hantronix.

When I build prototypes of keypads I like to use what are referred to as TACT switches. They are SPST normally open push buttons. Here is a link to a catalog page of DigiKey Tact Switches. They are really inexpensive, have through hole leads so they work on a proto plug board and give a good feel. As you look into tact switches you will see that there are MANY types available.

Hope this helps.
Michael Karas