It's just the main piece.
Yes it will link with the rest.
Yes it's worth 25 CCs
I took the advice and gemmed my MA to max, so that I can make CCs in 6 hr. I got the needed 25, just in time for the library to appear, and crafted it. With a little trial and error, I figured out I needed to put the library in the middle, so that all the other components are touching it. Now just have to sit back and let the untold riches roll in, lol.
I ended up having to make nearly all 25 CCs, due to having played myself into a corner where I'm always short on supplies. I can only make enough troops for tournaments or Spire, but not both. I'm going to start a new thread to ask for advice on this.