To be clear, Interference Immunity would be for severe interference, BUT that access point would typically change channels before Interference Immunity would be needed. I have only seen two times in 8 years that Interference Immunity needed to be used, and it was very extreme. Bluetooth does have some interference, but unless it is like 30 bluetooth devices, I would look at the RF utilization before doing anything.
You could, across the board, lower the transmit power of the 2.4ghz radios, because they definitely propagate further than the 5ghz band.