Originally Posted by dwig
You can change Viconia's alignment if you romance her.

I am well aware that you can, however you still have to handle her being evil for all of SoA and large parts of ToB. Parts in which for example your reputation may not exceed 18, or Viconia will leave (like all evil characters).

I remember first time I played Baldurs Gate, I simply disabled AI all the time so I could have Edwin in party with reputation 20. Not sure if that even works anymore with the EEs.