Now I'm also trying to recover the BCH from those same addresses. What would you advise to do to do that? I tried just relaying a BTC transaction on the BCH network to transfer the coins but BCH transactions must have an additional opcode to avoid chain jumping.
I assume the person that helped you, just gave you a "unsigned" transaction that you then signed and broadcast? If so, just use the same unsigned transaction and sign it with the "BCH signer" instead of the default one... refer: https://bitcointalksearch.org/topic/using-armory-on-the-bch-chain-2070058
Then broadcast that transaction on the BCH network... try http://blockdozer.com/insight/tx/send or https://pool.viabtc.com/tools/BCC/broadcast/