No... you can't just import the private keys for a MultiSig wallet, because each address has at least 2 keys required to be able to sign the transaction(s). If you import a private key, you'll end up with a "normal" '1' bitcoin address that only has 1 key... and won't actually contain any coins.
You'd probably be able to do it by crafting a MultiSig transaction manually... but honestly, you're probably better off trying to get Electron Cash with
the new MultiSig patch running from sources...
Having said that, even with MultiSig patch, be aware that 2FA will still not work, because TrustedCoin will still be signing the transaction as BTC which will cause it to fail. If you have 2FA, you need to restore from seed and disable 2FA when prompted to "keep or disable"... This will restore 2 of the 3 private keys into your ElectronCash wallet so you will be able to sign the BCC transactions correctly.