Won't need PCV valve and check valve with a proper catch can setup.
Mike brightside or Jason Drew will be able to help you with the valve cover and can both make it pretty after. Also what's your plan with the valve cover? why three?
I would raise the price of the COP a fair bit because you should have a booster in there, as mentioned many times stock system is good for 500hp+ so you are just throwing money away for anything less than that.
I would go with the 16g for quicker spool.
Ziggy has AN pump to rail kit so you can see what the cost is like.