Should i McGyver an open loop op amp (since it's the only thing i've got at hand right now) to convert the the signals?
That won't work as the I2C data signal is bidirectional.
What ever else you have as decoupling you need a 0.1uF ceramic capacitor to cope with the high frequencies 10uF and 2.2uF alone will not cut it.
I would also add another ceramic cap on each sensor.