(Canada) Is there a way to structure this?

[Brianne H.]

I am selling a house (technically a primary residence, but it's a finished flip) and I am wondering if there's a way to do the following: 

An option I would like to consider is selling the house with $0 down for the buyer. Ideally the buyer would have decent credit and income, they just haven't saved up a 5% down payment. If I sell the house for $375k, I would keep 5% ($18,750) in the deal (their down payment), and they would get a mortgage for 95% of the loan. The 5% down would be registered on title as a caveat/encumbrance to be paid out when they sell or refi, with a small % of the equity that's building up in the property, in exchange for keeping the 5% in the deal. 

Benefits are I would be walking away now with an amount of profit I'm happy with, and my money in the property is slowly growing over time. The buyer is able to buy a house now without needing to save for a few years, and they would just pay their closing costs. This is quite similar to how the Attainable Homes Program works, but with a few differences. 

Now my question is, how to make this work? Any mortgages that are over 80% LTV require CMHC or Genworth insurance, and I'm thinking they're going to frown on the 5% not coming from the buyer's own funds. Will the buyer have any issues getting a mortgage for it? Is it easy enough to come up with an agreement between seller and buyer for the 5% down payment that gets registered on title? Is there anything I'm missing? Thanks in advance

Ultimately I do not want to be a registered owner on title (I want to move on to other properties and don't want this to affect my debt ratios), and I would like to walk away with cash from the appreciation from the flip.