Note all investments, including real estate, carry the risk of loss in addition to possibility of gain. 

.- I could go traditional loan, using primary home HELOC as down payment, so effectively carrying two notes (down payment with higher HELOC rate, balance with current mortgage rate). - credit score is above 800.Any guidance on above options or ideas on other financing scenarios would be greatly appreciated.Thanks so much!

i personally use my regular phone but you could use a google voice number or an actual physical work phone with a different line. i'd do google voice so you're not carrying around 2 phones. :)

Assuming you have a decent income, you'll just carry over those losses as PAL.Seeing that you will be in a 2family, the deductible expenses are generally split in half.Hope that helps. 

Is you would have to qualify yourself carrying the whole mortgage, as if you did a 2 unit building we can count 75% of the rental income to help you qualify.

Essentially we carry back about $1,350,000 at 10% wrapped around a $620,000 note at 4%.  

This would carry a lot more consequences since this is the CRA and you are trying to avoid pay taxes.Not sure who is giving you advice, but I would be careful. 

I have been finding tired landlords who carry back for me, particularly on the barrier island in our high priced touristy market. 

If the seller is refusing to carry out these repairs, negotiate a seller credit for the cost of the repairs - have contractors give you an estimate in writing and provide a copy to the seller during your negotiations.

I think Installments sound strange and like a lot of problems waiting to happen, not to mention the risk of not being able to sell and then being out the carry costs, etc.