1) Which server do you mean? Perhaps, I am not getting the whole picture here. You said that the purpose of the MakeAPI server is to store metadata. Do you mean metadata comes to MakeAPI and it validates it one extra time before storing it? 
4) So we test.js is an additional checkpoint in the MakeAPI which will catch errors that could slip unnoticed when a Make comes from the tool? (Is it the webmaker where the Makes are made?)