spend from p2sh with bitcoinj
Based on your example it looks like you are signing the same sighash twice, so it only looks like one key signed. 

This example might help: https://github.com/magmahindenburg/MultisigExamples/blob/master/src/se/moar/bitcoin/multisig/MultisigPresentation.java

    // Sign the first part of the transaction using private key #1
    Sha256Hash sighash = spendTx.hashForSignature(0, redeemScript, Transaction.SigHash.ALL, false);
    ECKey.ECDSASignature ecdsaSignature = key1.sign(sighash);
    TransactionSignature transactionSignarture = new TransactionSignature(ecdsaSignature, Transaction.SigHash.ALL, false);

    // Create the sighash2 using the redeem script
    Sha256Hash sighash2 = spendTx.hashForSignature(0, redeemScript, Transaction.sighash2.ALL, false);
    ECKey.ECDSASignature secondSignature;

    // Take out the key and sign the signhash
    ECKey key2 = createKeyFromSha256Passphrase("Super secret key 2");
    secondSignature = key2.sign(sighash2);

    // Add the second signature to the signature list
    TransactionSignature transactionSignarture = new TransactionSignature(secondSignature, Transaction.sighash2.ALL, false);
    signatureList.add(transactionSignarture);

    // Rebuild p2sh multisig input script
    inputScript = ScriptBuilder.createP2SHMultiSigInputScript(signatureList, redeemScript);
    spendTx.getInput(0).setScriptSig(inputScript);

    System.out.println(byteArrayToHex(spendTx.bitcoinSerialize()));