Hayden is just down the road from me. Welcome to the neighborhood!
This area seems like it won’t slow down growing. Folks seem to still me heading here even more as they watch their state governments during this pandemic.
The first question for the county is if they will require a site disturbance plan if it is mapped as steep in their GIS layer.
https://www.kcgov.us/DocumentCenter/View/1459/Site-Disturbance-Application-PDF

You’re probably over 10% slope and within 500’ of water so you’ll have to have a plan. It’s not too difficult but there will be some extra hoops and costs.