Once again, I will ask stoffe. Also, I'm not sure it's possible to make powers that only the AI get, though you could try removing the forcehostile and forcefriendly entries in the spells.2da row (set them to ****).
As for just mirroring the K1R difficulty option, all you need is KotOR Tool. You'd open the difficultyopt.2da file in KotOR Tool, go to the last row, set the name column to 1322, change the label column to "Impossible", and the last entry in that row is the multiplier effect for the difficulty setting. You can adjust that yourself, but for reference, K1R sets it to 3.0, literally double Difficult.
You would then click somewhere else in the file and then save the .2da to your Override folder.