From what you've said, you handled it appropriately. That is to say you advised the buyers on what their potential exposure to having to pay commissions, etc., might be should they walk away from the deal. I don't think that advisement could be considered coercive. So long as you didn't say, "We have every intention of doing this to you", or something similar.

Neither is it coercive to avail them of resources for their daughter from which they can choose.

So, on the off chance that things for them go totally wrong for them having relocated (in their minds), and they have feelings that are beyond remorse (feeling rail-roaded) and they're looking for someone to blame, I think you're fairly firewalled as best you can be.