Looking good, followed your thread here a while back. Your shop and how you built it is really cool. My brother lives in Port Angeles Washington so i've visited Seattle each year for the last few years. Would be cool to check out your shop next time. Your house reminds me of the homes near the...
Just went through your thread and saw that the garage ended up being smaller than you had originally wanted, something you might consider if it's not too late is provision to add an lean-to off one of the sides-like a carport and then maybe try to enclose it later, if nothing else it would be...
i think this GJ thread might give you some ideas on your property slope question. https://www.garagejournal.com/forum/showthread.php?t=251805&highlight=roof+garden&page=11
I completely understand and agree with the ordinance which was written to prevent mansion-izing, i think if you go meet with a planner and explain it's a shop, you might be able to get a variance or some kind of conditional use waiver.
Whatever happens, i'd work your design to take advantage...
If this ends up being the case, you could always buy the steel building framework and instead of metal sheeting have it finished out in something else. Google "artisan panels steel building" this is a more classic option to finish out a steel building and might go better with your modern home...