Yes you can add the ‘features’ to the Room mailbox. If you need to ‘schedule’ the projector or laptop then you should set up an “Equipment” mailbox to schedule the Equipment along with the Room.
To setup the “ResourceCustom” features assigned to a “Room” mailbox…
You have to setup the list of -ResourceCustom 'features' that may be added to a Room mailbox by using the “Set-ResourceConfig –ResourcePropertySchema Room/Projector,Room/Laptop etc “ to setup the list of 'features' available to ALL Room's.
To add the specific ‘feature’ to a Room use the "Set-Mailbox .... -ResouceCustom Projector,Laptop "
This is more to identify what is actually in the Room vs. trying to show what Equipment can be scheduled in the room.
Also set the room capacity using "Set-Mailbox ... -ResourceCapacity 9999"
Both the Capacity and features will display in a properly configured Rooms display in the Address Book ("Capacity" and "Description" fields in the Address Book).
Capacity is just a numeric string (no numeric use) and the list of ‘features’ assigned from the ResourcePropertySchema list are strung together after the word Room in the Description field separated by commas. Again though all possible room features are known to the system via the ResourcePropertySchema there are no Room search features to take advantage of knowing what features are available in the Room’s.
You just have to eyeball both capacity and room 'features' when searching for rooms.