It is true that we were able to recognize this profit by offsetting ordinary income from other personal sources... this benefit would not have been available without it, and may not be available in the future, but it was certainly there for us in ‘18.

The house above is not an ordinary boring tri-level and is the sort that depends on the detail/design.

Starting out I would read Everyday Millionaires -How Ordinary People Built Extraordinary Wealth and You Can Too by Chris Hogan.   

Rental real estate is not subject to SE taxes unless (1) the taxpayer is a dealer and the property is used in the taxpayer's ordinary trade or business as a dealer, (2) the taxpayer is renting out farmland under very specific fact patterns, (3) hotel-like services are provided with the rental, or (4) the taxpayer is renting space in parking lots, warehouses, or storage units. 

Because you can leave more money inside the 1031 where it will stay tax deferred.and the 3rd option (just because I'm a Goldilocks guy) is to not take a commission (you don't pay ordinary income tax). 

Although no single factor is determinative, the combination of several factors supporting a particular result is sufficient for a court to decide whether a taxpayer held property for sale to customers in the ordinary course of a trade or business.

So $500/month is not out of the ordinary here.

It's a former Brit colony so follows some of their rules - stamp duty, etc. 

No guarantees here, what if you get pigeon holed into a very ordinary strategy?

I mean it is disqualified from the tax treatment** You can borrow money and use it to buy things inside of an IRA, but it makes the income derived from said activities subject to immediate taxation at your ordinary income tax rate.