Something that would be interesting is if they actually caused real problems with the Tieflings staying at the Grove.
I think that evil or renegade options are less appealing when there's no real reason behind them other than just being evil for the sake of evil.

But what if the Tiefling and their sudden appearance actually caused a famine and NPC's started to die?
If the issues with the Tieflings staying at the Grove became an actual part of the game then the other options like forcing them out or whatever would become more appealing and understandable.
But when there's no actual issues that occur because of it then it feels less impactful and easier to just go down the good route.