Look at the lien instrument (the mortgage or trust deed) to determine if you have a lien on and can foreclose on the dwelling. It isn’t how you code the loan that matters. Given that, if the debtor discovers you have coded the loan in such a manner, I believe it would give them an affirmative defense against your foreclosure, because you do not consider that a lien exists on the dwelling. Therefore, there would be a question about good faith on the party of the lender.
As for RESPA and RoR, I think yes, they would be subject to both RESPA and RoR.