In BG3, as in BG1 and BG2, a lot of things can be done either for "good" reasons or for "evil" - whether good or evil depends on the alignment of your main character. This is especially true when it comes to the Throne of Bhaal (which completes the story line of BG1&2). Both "good" and "evil" parties must do the technically same battles/killings.
In BG3, almost all the "evil" deeds as outlined in the OP for an evil playthrough can be done by a "good" party (though admittedly there are a few limitations/exceptions). In many cases, players who swear to be "good" don't even have to figure out an excuse for doing unnecessary killings or slaughtering while pretending to stay on a "true" good path. The game will thoughtfully provides all kinds of excuses for a "good" party to be "evil" or for an "evil" party to be "good".
I actually feel like a good character has the potential to be the MOST evil. What I mean by this is, if you're evil outright, you cut off the opportunity to be even more evil later on. If you're good the entire playthrough and then make EXTREMELY evil decisions at critical moments, it adds betrayal to just plain evil. Take these for example:
- Turning Shadowheart Selunite, have her betray Shar, then give her to Viconia
- Save Nightsong, reunite her with Isobel, then betray Dame Aylin to Lorroakan
- Help Astarion, then turn him over to Cazador
- Be good the entire playthrough, then at the last minute, become the Absolute.
