The answer was very simple. If you self-employed person and the income you was reporting to CRA in your Notice of Assessment (NOA) is enough to qualify for a mortgage, you need only 5% down. And if the amount you have in your NOA is not enough, you can combine it with your spouse.
But what about 10% down, why most of the websites including government websites tell than self-employed should provide 10%. That is right, in case if you can not provide sufficient proof of income, you must put down at least 10%, and you will have to find a lender who uses Genworth or Canada Guaranty.
Talk with a bank or mortgage broker. After providing your income to them, you will be able to get a clear answer of what amount of mortgage you qualify and how much down payment you need.
Buying your first property looks like a lot of work, but in fact, it is not, most of the job done by your real estate agent, mortgage broker, and lawyer. All then you need to do is provide documents they ask from you.