I need a wiring solution for an unusual situation
I would say yes, although you are swapping one code violation for another. The fridge CAN be on with the small appliance counter circuit, but the DW cannot (which is how you have it now). 

If the fridge is kept off the SABC (small appliance branch circuit) then it must be on it's own circuit. At the same time, I do agree that having the fridge on with the disposal is the lesser of two evils as opposed to having it on with the counter circuit and GFI protected. 

I still do NOT like that the DW is on with the SABC. The DW is likely more of a draw than the fridge, but you have the option of not using the DW at times when small appliances are being used. The fridge does not allow you this flexibility.

I am not an advocate of code violations, but swapping a minor code violation for an even lesser one IMO is not a bad thing to do. 

Best case scenario: 


Combine the DW and disposal on the 20A circuit.
Give the refer it's own new 15 or 20A circuit. 
Keep the two SABC's dedicated to the counter receptacles.