I'm also joining the ranks of Kamado Joe Classic owners on Monday :) I'm looking forward to it and good luck with yours as well!
As for your questions...
Use lump charcoal.
There is no break in or seasoning needed.
I'd suggest buying the heat deflector from Kamado Joe or have your choice of the third-party setups for indirect grilling/smoking.
Spend some time learning how to control the temperature in the Kamado with the air vents. This thing is a really great convection oven that you can cook anything in once you learn to manage the temps.
Use it often!
Kamado Joe Big Joe ° Kamado Joe Classic ° Old Country BBQ Pits Brazos Offset
UDS ° Traeger Lil' Texas Elite