It's pretty simple-- you use Name Input Processing to change the name. You use Show Choices and Change Actor Class to change the class. Change Actor Graphic is how you change the graphic, and you can use Show Choices with that.
Well, except that Show Choices only can show a few options. If you have more than four classes or graphics available, you'll need a more complicated system. The way that I'd normally do it is by having the Actor's charset start off as something like a light to use as a cursor, then have them sent to a map with Events depicting all the possible graphics that they can use. Make the Event Change Actor Graphic to the graphic of the event. It's simple, and pretty cool.