Land Banking Deal

Looking at a land deal that is zoned for apartments, planning about 250 or so. We can't come out of ground because we don't have the sewer allocation, which we need to accumulate from the county. Currently looking to change that process and are hopeful there will be some relief, which we think is coming. Can get this deal under contract and have 3 years before we need to close to give us 3 shots to accumulate sewer allocations. Assume we pay 1X /unit if dont have allocations and 2x / unit for every allocation we do have. Could extend for another 3 years if seller sees we are getting seats in order to get the price they want. At that point we are entitled and can go. If we need to close without seats and becomes a land play until we have the school seats. It cost us $2M. We are already $500K in on GP side for entitlements..how does that $2M fall in capital stack, not familiar with land deals? And what may someone want for that? $2M back plus pref and part of deal? need to sell for atleast 5M so they can double up on their $ because of the risk here? Divy 20% of capital stack to the purchase of the land? so if we are all in for $2.5M and sell for $4, they get 20% of that profit???