Hi,
I don't see a problem to use one buffered ref.
But the load at the Ref voltage is switching, to stabilise it I recommend to use RC bypass to avoid ringing and coupling to the other channels..
Tho outputs of each left side opamp will saturate at positive voltage during clipping. The output will saturate and the difference voltage at it's input also is big and thus the input stage will saturate also.
Both leads to time delay and coming out of clipping state will be delayed and distorted a little.
If possible try to avoid opamp saturating. Some Opamps may suffer from phase reversal when the inputs are near supply rails.
Some Opamps have limited differential input voltage range...
Consider this when selecting opamps.
Klaus