How do you regenerate all 2-of-2 multisig addresses from two xPrivkeys?
Trying to generate all possible combinations would probably go on forever. I would suggest you figure out what the derivation path used on you BCH wallet was (will probably be /m/44'/145'/0') and then loop through different combinations to generate different multisig addresses.

How come you only have the xPrivkeys and not the mnemonic words? 

If you had the mnemonic words I would suggest recreating the wallet on the same wallet app by importing your seeds and the wallet should scan addresses associated with those keys.