I think this is a distinct category of things that we will probably keep running into. In my industry we call the peocess of making third-party widgets talk to each "Integration" so when there is a clear purpose in someone's question where they take a component like BTCRelay, or Maker's DAI stablecoin, I would think a tag like "Contract-Integration" would fit quite nicely.
Integration I feel is distinct from debugging, because there may be nothing wrong yet tbat needs fixing. You just might need some documentation explained more clealry for you to proceed. I also expect the most common pieces of infrastructure (Coin API, NameReg, etc.) to end up with canonical answers for how to integrate them with you custom contract.
So, specifically for a question like the example linked, I would suggest the tag "Contract-Integration".