You won't need extra fastpass tickets if you're going outside school holidays

. The fastpasses sold on ebay are extra ones, with no expiry. They are useful only if you're intending going to DLRP at busy times. Its also worth noting that there aren't that many rides in DLRP which have fastpass machines anyway.
If you use Extra Magic Hours for doing rides in Fantasyland and Discoveryland, you may only need fastpass for Big Thunder Mountain in the main park, and Tower of Terror in the Studios.
There are no safes in the rooms at the Cheyenne, but there are safes at reception, which you can use free (just don't lose your safe key, as they will charge you to replace it).
I hope you all have a fabulous time

!