You get the tax benefits of owning it through the interest (that someone else is paying) and the depreciation.

So it makes sense to take the depreciation.You may want to seek the advice of a chartered accountant in Canada and a CPA in the US to make sure you are taking advantage of all of the benefits available to you.

So that could be a benefit to the seller.If the seller is wanting to do another 1031 then they will have to do some specific things to accomplish both the 1031 and owner carry.The note, as a proceed of the sale has to go into their 1031 exchange account. 

That’s not even counting rental increases over time, mortgage principal paydown, and tax benefits. 

Does grandfather receive medical benefits that he cannot have real estate anymore/ which prevent him from needed Medicare?

That said, you do miss out on some of the benefits of a brick and mortar brokerage you might find, in my opinion.

They mow the two mounds of grass at the front entrance but don’t mow the entire width along the Main Street, I get zero benefit from the $800/yr and frankly am fed up. 

There's probably a benefit to being an early adopter in that you take care of it before everyone else "has to" do it, but if you're too early then the infrastructure/products/know-how isn't there as much so you pay more than if you wait until demand is more widespread.Most folks I know, including myself, are taking a "wait and see" approach at the moment, but obviously folks that owner occupy might act earlier especially since it could benefit them personally.Now is a good time to recommend RISE Engineering, which does free energy audits of residential properties and then reduced-cost work if you do decide to implement some/all of their suggested improvements.My understanding is that it's free for the audit and reduced-cost for the work, because they get funded partly from charges everyone already pays on their electric/energy bills - i.e., it's subsidized by a tax we're already paying.

So no further benefit to you. 

Our CPA allowed all depreciation and tax benefits to flow to all members of the LLC that way as well.