You'll need 3/16" OD brake line components. Your caliper is a dual piston model with 2 brake line inlets, so If your master cylinder only has 1 outlet, you'll also need a T-fitting.
I cant see anything missing from your master cylinder pic, post a new pic showing what you mean.
If your spindles are matching left and right pair, all the angles should be a perfect mirror-image of each other. If your unsure I'd ask about that on the Birel forum.
Then it sounds like all you'll need to complete your axle is a sprocket and sprocket hub, keys and some metric bolts from a hardware store. You can buy a hub and keys most anywhere but we still need to decide on the tooth count for your #35 pitch sprocket.
I couldn't find any 40mm. sprocket hubs listed at that kartsandparts shop, but its a common part so you might ask his price on one. plus the 4-keys you'll need. I've ordered parts form him before, he shipps fast and i really like that his prices include shipping.
Or the Burris 40mm sprocket hub here is a fair price:
http://www.out2win.com/catalog/sprkthub.html
The 4 Keys you'll need are probably listed here:
http://www.out2win.com/catalog/axleeuro.html#7
Then you could go ahead and assemble the axle now and instal a split-sprocket:
http://www.out2win.com/catalog/sprkt_axle.html later after you decide on a motor and we figure out your gearing.