Me too... I'm still struggling with the "OP imported 5 keys, ended up with a wallet with 10s/100s of addresses" part.

In all honesty, it sounds like the wallet file is corrupted (KeyError crashes, inability to send funds or see private keys etc), and the OP has unfortunately sent coins to addresses that are stored in the wallet file but the private keys for these addresses are not or are corrupted

In my opinion, it is going to be very hard to troubleshoot and/or say definitively what the actual problem is without someone with the technical knowledge taking a look at the wallet file... maybe a screen show with the "secret" stuff redacted?

@Lexx2k... Is your wallet file password protected and/or fully encrypted? Or are you able to view the basic structure of the wallet file in a text editor?