And the fact that the original spec was claris/octalink doesn't mean that those are somehow a better fit and will not give you any problem. Bottom bracket area creaks are notoriously hard to pin down, since a lot of things can make noise that seems to come from that area. 2000 miles seems low for needing to replace a bottom bracket, and since it got better when you cleaned it, it sounds like the noise might be the BB moving in the frame, not any problem with the bearings/internals. I would double-check that the BB is securely in the frame first, then look for other possible noise sources like loose chainring bolts or the cranks not being tight onto the spindle. But that's just guessing.