If you were able to load the wallet in Bitcoin Core and run
dumpwallet then all you need are the privkeys starting with "5" or "L" or "K". You can import all of those into an Electrum wallet (
https://electrum.org/#download - Read the HOWTO verify guide here:
https://bitcointalk.org/index.php?topic=5240594.msg54223763#msg54223763)
As I said, it seems that you're having issues with PyWallet due to the updates... you'd either need to switch back to Python2.7 and my old version of PyWallet... or wait for JackJack to get a less "unstable" version of the new Python3 compatible Pywallet up and running.
But it's not necessary if the wallet.dat opens in Bitcoin Core... you'd just be dumping the same info... so I'd just forget about PyWallet for now.
Focus on importing those private keys into another wallet, and check to see if any transaction history is found (and hopefully a positive balance!

)