You'll want to consider full costs upfront and an architect + contractor team is helpful in that process.

But if not BankofAmer, would another mortgage lender take on the 2 mortgages and blend the interest rates together based on my credit and possibly even cash flow?

Your cash flow is limited there so hopefully the property is in good shape.You would likely be better to use a HELOC to take to invest in a quadplex or two-family if you wanted to go multi because you won't see a property at 2.875% ever again most likely.

Real estate in Canada is just way too expensive and impossible to get positive cash flow. 

Additionally, I am looking for a real estate investment opportunity, ideally something that produces decent cash flow. 

In addition, the deals will be based on long-term rental outlook, but we are going to see how a mid-term rental strategy pans out for the higher cash flow in the short term.

I live in one and rent the other for $400 cash flow.

An FHA loan can be assumed by anyone who qualifies for the loan.But in all cases, the new borrower will most likely have to bring an enormous amount of cash to closing.

Hoard the cash!

I am currently running ads to rent out the entire property and will be able to bring in $500-$800 in cash flow after all property expenses and have received multiple application requests.