If so what is the specific requirement addressing the alleged outstanding interest?

You’d need an estoppel to effectively get that info.And yes, they could lie on an estoppel, but at least you’d be clear on what the CURRENT terms of the tenancy are as they alleged them to be, and then the buyer can make an informed decision on whether or not to proceed to closing.And if you do close, you get to hold them to whatever they said on the estoppel because it’s presumed to be true AND binding on both the tenant and landlord.