You can defer capital gains taxes on the ADU through the 1031 exchange, while the portion of the property you’ll use as your primary residence would not qualify and would be subject to capital gains tax as usual.

What you're proposing is the conversion of ordinary income subject to SE taxes into deferred capital gain, OR potential exclusion of the income all-together under IRC Sec 121 if the property is to be your residence.I've seen no reasonable basis for such a position.

Those with real subject matter expertise get the year 1 return that no longer exists in more mature national park markets. 

Yes, in my experience appraisers have to pull COMPS that are in the same city as the subject property.

Yes, those things were listed by someone named Mike Hern who has been deleted.He is the pro on the subject, but that subject is no longer welcome on BP apparently.

Last 6 months what has sold, for how much, how long did it take, an interactive map showing all comps and subject house. 

Here's an overview as well as my understanding of the tax implications.I'll start with the US Tax implications:As a foreign investor, you’ll be subject to U.S. federal income tax on the income generated by your U.S. real estate investments.

They apply, but you are just subject to gift tax at that point, which does not actually result in a tax bill for you, but a reduction in your total giftable allowance which is ~13M dollars. 

I youtubed everything and watch several other videos on the same subject.

All if this is subject to negotiation.