PSoC: Question on Productizing using a PSoC
I'm currently in the same situation as you. 
As for the legality of using PSOC's as components I would imagine it's the same as an arduino, and it's just a 'component'.
(I started a thread on the cypress forums asking about this, still waiting for a solid response) https://community.cypress.com/thread/32917

As for asking about price, that's something you will have to search for to get the best price, maybe even phoning and talking to suppliers to try to haggle those better deals at lower volumes. 

If you're a student or alumni see if your university (or even others) have business development programmes.  I myself am enrolled in one such program and the support and resources available make a world of difference. 

Don't underestimate the power of networking!