Hi Ryan, welcome to BP!
As an Asheville RE Broker, when we have lots/land that we are showing, we usually walk the property with the client and a builder to determine roughly how hard it will be to build before going under contract to see if it's even worth pursuing. That builder can be one that the client selected, one that we recommend, or in some cases one that is required by the development if it's in a subdivision with such requirements. Given the terrain here, it helps to have a builder who has a good engineer they work well with too.
Then the buyer can put the property under contract and use the due diligence (inspection) period to get into more details and pay for tests such as the perk test/septic permit if needed, discussions and analysis from an engineer and the builder/architect to make sure all the extra build costs are known before closing on the land, have a survey done, and whatever else is desired. We've even seen folks drill the well in due diligence just to make sure they find water before buying the property. Although there will be costs associated with getting all of that done, it's far better to have all that before you close on the property just incase something comes up that would make the property unusable, way too expensive to build on, or doesn't go as planned.
Hope that helps!
Pat