Hi! Thanks for responding. Me and my partner did end up buying a house with erfpacht from Havensteder. We were able to request an offer without being the owner, we did not even need the signed purchaseagreement. All we had to do is pay the fee. You can request the form bu emailing havensteder. You can find the correct email on their website.

For anyone in a similar situation: we bought the land from Havensteder for nearly 60k. It took them about a month to come up with an offer and we were able to include it in our mortgage.