Won't count as a package because you booked a room-only. If you want to add a dining plan, you need to call WDW and ask for a ticketless package. They will cancel your room-only reservation and book a new room part of that package. If you don't want to add a dining plan, no need to change anything. As soon as you get your tickets, link them to your
MDE to book your FP+! I did the ticketless package last summer (my tickets were from Airmiles and
Undercover Tourist) with a room at CSR and the regular dining plan. I thought of doing that again this winter but it was cheaper for me to book my room at Pop thru Orbitz (no possibility of converting to a package) and get my tickets from Undercover Tourists.
For the mail, you should get something at home. When I booked from Disney directly in the past I always got something. But not this time but I think it's because I booked thru Orbitz. Only the magic bands are delivered directly to the resort because of the RFID chip I think.