Help with shopping for Plywood

As a relatively new woodworker and a soon to be father I am hoping to build some shelving, a desk, a router table, and a bookshelf.

I had hoped to use Apple Ply or Baltic birch for the shelving, router table, and the bookshelf, as I know it's sturdy and I like the look of the edges when finished. I was hoping to make the desk with walnut, and frame it with solid walnut.

I had heard that home depot's special order department could now get you anything from Columbia Forest Products. I have been emailing back and forth, and can't seem to understand what is the best option.  I had asked for the closest thing to baltic birch or apple ply, and was told that was their euro ply.  She quoted me the europly cores without a veneer at first and then with, and the price suddenly doubled.  i didn't understand the difference, as I thought the core was made up of even veneers for baltic birch/ europly. As I don't know if I can swing the boards at twice the price I was wondering what to order.

Here is the item description for the 1/2" europly core:

 7/16" 97" x 49" Europly PLUS VC NAUF Core

and for the 1/2" with veneer:

 PANEL: 1/2", 48.5" X 96.5", Europly PLUS VC, B, 1, R/C Spl, Birch, R/C, Birch, PureBond FF PACKAGING: 0% Shop Allowable           

This was for the 3/4" europly:

 FSC-SW-COC-000065 11/16" 97" x 49" Europly PLUS VC FSC Mixed Credit NAUF Core   

and with the veneer:

 PANEL: 3/4", 48.5" X 96.5", Europly PLUS VC, B, 1, R/C Spl, Birch, R/C, Birch, PureBond FF PACKAGING: 0% Shop Allowable    

There were two options for the walnut that were around the same price, but I didn't truly understand the difference:

 3/4" A1 Walnut      * CARB Phase 2 Compliant HWPW-VC; NAF Resin Certified: HPVA TPC-8                                

   Or

  3/4" 4' X 8' Composed Poplar VC A 3 P/S Walnut R/C Birch PureBond FF                                

                 * CARB Phase 2 Compliant HWPW-VC; NAF Resin Certified: HPVA TPC-8                                

                 * Use Meinan Core Only 

Any explanation/advice on what the description means and what my best option would be, would be appreciated. I was thinking of starting with 2 or 3 sheets of 1/2" and 3/4" baltic birch and the one sheet of walnut.