Thanks for quick response. I gave my SIN no. alone, so they can access tax return info from CRA. If they use the latest 3 years taxes filed, I hope its before April 2019. My EI+CCB alone is not enough to qualify.They may or may not asked to see your 2018 NOA unless they have reasons to believe that you may not meet the LICO in that year. I have not seen a case where CIC asked to see the 4th NOA. They process SA based on the information you already provided.
By the way, when you calculate your income, make sure you add EI parental income and Canada child benefit. Federal and provincial child benefits can add up to $6,000 depending on your combined income. CCB is not government assistance, as it is named "benefits" just like tax benefits. They used to have child tax credit for income tax purpose. But, it was replaced by CCB.