Dream humidor construction in progress- help?!

So a new co-worker and friend of mine Darrell happens to have experience building cabinetry / jewelry boxes / display cases ect.... I rough sketched plans to him and he became very enthusiastic about our project to build my dream humidor. I will do my best to describe the dimensions and design and I have/ and will inevitably have more questions... I'd love any and everyone's feedback in this endeavor....

DESCRIPTION: (to the best of my abilities)

The Humidor internal dimensions are Height:17in Width:18in Depth: 8in
The Humidor (more or less) consists of 3 parts,
--Base: containing 1 accessory Drawer (non humidified), Humidification bay, slotted overlay, and 8in wall for box storage, the Wall is of single slot and groove design upon which the next layer rests.
--Single storage: 5in wall with stops that allow top portion of humidor to be removed to allow direct access to box storage,this portion will contain 2 trays with the dimensions 2.5in x 18in x 8in
--Lid : Humidification bay of 1 inch for bead storage resting on slotted panel directly over single storage, then a 1 in hardwood top.

QUESTIONS: (HELP!)

1) Anyone know of a good place to get wood? (ha)
2) Does the inside HAVE to be lined with Spanish Cedar? or will just Cedar work? How thick of a lining?
3) Darrell thinks a 1/4 inch wall, and tongue and groove seals separating the compartments will hold humidity, anyone know/have anything to say about this?
4) What beads should I use? everyone on here seems viciously loyal to their bead brands.

ANY AND ALL CONSTRUCTIVE COMMENTS WELCOMED AND GREATLY APPRECIATED!!!!

Thanks Guys,

Rob