RE: How to reduce I2C bus noise
Not sure what you mean about noise, relative to what?
You've got 200pF of capacitance on each signal, this is not really necessary. I suspect you've actually got local ground noise which is being coupled into your signals through these capacitors. What happens if you remove the caps?
First thing, verify how much noise there is on the power supply relative to various ground points around the board (e.g. on each IC) by getting a close ground with your 'scope. Do you have a solid ground plane? It sounds a bit to me like that the grounds might be just tracks causing local ringing of the ground signals which in turn couple into the signals via the caps - make sure each IC has 100nF decoupler close to the power pins, and that there's some bulk capacitance (say 10uF caps) spread around the board on your 3.3V power.