I think you packed in too many questions too fast...
Plus they are rather trivial questions that are suprising you opened a shop without knowing already!
You are right the differences between a cappuccino and latte is foam, this continues for the majority of espresso drinks.(they all have easy to remember italian names too! like my favorite; Cafe macchiato, Macchiato for short.)
Cappuccino: one shot espresso with 3/4 cup milk and a dollop of froth.
Latte: one shot espresso with 1/2 cup steamed milk and plenty of froth.
Macchiato: one shot espresso with just a dollop of froth.
Of course not to get into the little details behind descriptive words (think adjectives in english) double, triple, ristretto, lungo, mocha, and then come the low-fat non-fat etc... and the syrup flavors (ginger, rasberry, bannana, etc..)
needless to say I highly recommend a book about $30 to catch yourself up, or befriend a good barista asap!