1- the spring in the middle looks like the replacement/shorter servo spring for a billet servo. Did you order a CK billet servo also? How tall and wide is the spring? (I will compare it against mine)
2. I can't really answer this question in confidence. Your 1/2 and 3/4 springs look completely different from mine. And I have 3 kits from ck. in my kits, The 1/2 springs are have a really large diameter and have thick coils. These springs are painted yellow, and white. My 3/4 springs are both like either a redish or purple-ish color.
3. Yes you should have a o-ring seal on the piston.
4. Yes , you are correct, the cup is pictured on the right end. Just use some Vaseline to hold it in place while you install the valve.
5. One 3/4 spring, it assembly is Case, piston, then the spring sits inside of piston, the gasket, the sep. plate.(based on your power range and stall converter)
I omitted my 1/2 and 3/4 springs and pins per the instructions based on my application.