To make the custom player characters more interactive in cinematic discussions, voice recognition could be added, and the character on screen could mouth the words as they are spoken. For reference, here is a Skyrim mod that adds speech recognition so that you can speak the dialogue lines aloud to select them:
https://www.nexusmods.com/skyrimspecialedition/mods/16514Also, there should be different sets of dialogue choices depending on the player characters race, alignment and IQ level. A LE drow wizard with an IQ of 18 should have different dialogue choices than a CN halforc barbarian with an IQ of 3.