1 & 3 I used to buy Borax direct from Consolidated Borax (20 Mule team) a few metric tons at a time, I used a small amount for my developers, it's the same as Photo grade but not analytical. Any good chemical supplier can get you Borax.

2 You'd need to ask the Formulary what version they are selling, Kodalk/Sodium Metaborate was the Octahydrate.