One thing that you failed to contribute;
Is this house in a RURAL area, or is it in the middle of a RESIDENTIAL neighborhood?
Could it be that the mineral rights were sold when it was the middle of "nowhere", and someone thought it might be worth something, and now it might be worth $1?
Is complex question and the devil is in the details... i.e. depends on the document that conveyed the rights and for how long... the foreclosure may extinguish some title rights, but not all of them.
If there is confusion on the rights and of course value attached to it, then you may file a suit in court to "quiet title" this means making sense of it and the court ruling on who has what rights.
Best of luck!