All anyone can do is to try and make helpful suggestions based on direct experiences. And to humbly, point out something that doesn't look right on paper.
One of my neighbors decided to build a Barno. I should better say, they took over a failed attempt at a Barno that was started earlier by this neighbor's brother. The brother was use to living in Alaska, and had no concept of CODE. The brother put $200,000 into his back of the napkin design. None of it was code complaint. But he did get to a point where by it could be called an AG building.
When the other brother asked me what to do with the structure, I said leave it AG and start completely over some where else, on the property and build a new domestic dwelling. This advice was not followed, and they spend another $280,000 to make this building compliant. This is in 2007 money. They got the occupancy sign off in 2011.
To me personally, this house was an un-practical and esthetic nightmare. That ended up with 1,200 square feet of livable space, over the garage, and the "Garage" bit had to be turned in to a wood shop/man cave sort of area with a few couches around the wood stove.
The up stairs has only three spaces. A tiny bed room, a tiny bathroom and a very limited space, kitchen/living/dinning room. For near 1/2 million in 2007-2011 money. And you have to walk three flights of narrow stairs to get there and three flight down to get out because the stairway had to be fire rated and isolated from the garage part. And he had to build a very expensive secondary egress in the form of an outside stairway they never use.
Not saying your ideas are bad in any way, but I would pick the A frame ground level concept over the Barno. Or just stop right now, and rethink all your ideas, and look at a great deal of standard "Off the Shelf," plans that are available. You might find one that works and checks all the boxes: Or not.
It is a wonderful thing to design your own house and be involved with its construction.
I see an issue with trailering something in to the garage space, with how your driveway system is layed out. There isn't enough room. Just say'en.....