Were you able to accomplish what you wanted to accomplish? In this last post, the first input needs to sign the double-sha256 hash of:
0100000002ab39b37e4ab8d55dc043998d69c537c8c2fd6f588c12a81887d437bcf3261dac000000001976a914c44ceea4b4738e74483219e9af1435b7a0e8127788acffffffffab39b37e4ab8d55dc043998d69c537c8c2fd6f588c12a81887d437bcf3261dac0100000000ffffffff0100350c00000000001976a914c44ceea4b4738e74483219e9af1435b7a0e8127788ac0000000001000000
and the second key needs to sign the double-sha256 of
0100000002ab39b37e4ab8d55dc043998d69c537c8c2fd6f588c12a81887d437bcf3261dac0000000000ffffffffab39b37e4ab8d55dc043998d69c537c8c2fd6f588c12a81887d437bcf3261dac010000001976a9147db9fbceb81b5dc4cbcc84ab6b0cd9e57d1e392588acffffffff0100350c00000000001976a914c44ceea4b4738e74483219e9af1435b7a0e8127788ac0000000001000000
Notice that in both of them, the input that is not the one that's doing the signing is always set to 00, and then the signature type (SIGHASH_ALL aka 01) is appended to the end (01000000 -- aka 00000001 but reversed so the 01 is the left-most byte).
So the unsigned transaction that you are given to put on the website to sign is where all inputs are set to 00 and the signature type isn't on the end. Which looks like this:
0100000002ab39b37e4ab8d55dc043998d69c537c8c2fd6f588c12a81887d437bcf3261dac0000000000ffffffffab39b37e4ab8d55dc043998d69c537c8c2fd6f588c12a81887d437bcf3261dac0100000000ffffffff0100350c00000000001976a914c44ceea4b4738e74483219e9af1435b7a0e8127788ac00000000
So if you sign that separately with each and then in each position swap the 00 with the sig+pubkey, which will likely be:
[8a or 8b, the length of the sig+pubkey combo] followed by
[47 or 48, the length of the signature]
[30.......01, the DER signature, which will be 71 or 72 bytes long, ending in 01 aka SIGHASH_ALL] followed by
[41, the length of the uncompressed pubkey] followed by
[04......., the uncompressed pubkey]
So you swap each 00 with each key's sig+key data in the format above.
You probably already know this, because the last code-quote in your last post there looks correct syntactically, but the signatures just don't verify against the tx.