One thing to think about are the tax implications of being a Canadian paying US taxes.

Note - if you live in your property for 2 years out of the last 5, then you don’t pay taxes on the profit. 

I'm not a fan of flipping simply because I hate paying taxes when I don't have to.

Offer to pay them off in 5-10 years at a higher interest rate.

You can stack your personal 50%s up for separate ventures while still knocking out deals without your own capital2) Read Raising Private Capital by Matt Faircloth3) One LLC with the S Corp designation to pay yourself a reasonable salary from the flip profits.

Sometimes they forget to tell you that many tenants in Detroit don't pay (depending on the property manager skill and the type of tenant) - but taxes are very high in the city and so is insurance. 

The loan is 12 months, pulls twice a month, the interest is minimal because I'm paying it off so fast. 

If this is correct, how much are you cash flowing each month after you pay your operating expenses and make your loan payment?

I own all my toys, never seriously worry about money (I suspect everyone with any money always at least pays attention to it), spend my winters in Florida and rarely work in any sense (I do some consulting and side teaching) more than 10 hours a week.

Cost per lead (CPL) is crucial—it shows how much you're paying to get a potential seller or buyer’s info, and you want this as low as possible without sacrificing quality.