When you're in the business of dealing in options, you are in a different category than ma and pa doing a one time option deal, laws become applicable to dealers, such as RE licensing, SEC, Finance regulations, advertising, HUD regulations, accounting requirements and taxation as mentioned. 

The taxation is different, and you could end up paying twice.

Hello BP, I have this nagging thought in my head: will borrowing from one's 401k cause double taxation?

I understand that TIF effectively freezes the property tax at the pre-project value, but I don't understand how that could be used to fund a down payment on a project.  

Nearly all of the benefits of RE are related to Federal taxation and not State.

The biggest being borrowing from Canadian lenders - with no Canadian income, residency or credit history you may find yourself limited in the size of mortgage you can place (perhaps no more than 50% LTV).Your easiest approach may be to find a Canadian partner and work with them to acquire properties.Overall, the fundamentals of investing in real estate are the same, details will differ - particularly in areas of finance, regulation and taxation.  

You should also remember, if the building is your primary residence, than your input expenses {i.e. renovation costs} are not deductible from the proceeds of the sale ... this might very well negate any taxation benefit.

Keeping money to the end of the year won't have any more tax drawbacks, any income you can not deduct, towards expenses, would be taxed. one way to not owe the tax at the end of the year is if you sell a property and do a 1031 exchange ( like kind exchange ).

A benefit to you when you occupy a property for any 2 out of 10 years, is that the property increases in value over time, and you can exclude the capital gains from taxation. 

@Steve Vaughan There's a very good point you make regarding the taxation issues, if you rent for 12 months and a day, 366 days, your taxation when you sell (what the IRS charges you)  is a lot less then if you sell quickly (less than 12 months)See your CPA