The first point I would make is that, first of all, it is fine to say that the purpose of these policies is to create choices, but the reality is that the notion of choice, when circumstances constrain the number of options available to people, are false choices.
For example, the universal child care benefit, which provides a little bit over $100 per month for every young child under the age of 6, is not enough money for someone to get out the door to earn enough money to do anything. It creates the illusion that someone can choose to stay at home with an allowance of a little bit over $1,200 per year per child, but no one can live on $1,200 per year, and it creates the illusion that a person can choose instead to spend that $1,200 per year on child care. And that is also an illusion. So yes, there is a choice, but it's not a real choice.
One of the other policies you may describe as also being engineered by tax policy is income splitting. Income splitting is carefully designed and historically has always been carefully designed to keep more economic power in the hands of higher-income individuals. It arose from the English common law concept of coverture, which treated women as being part of their husband's beings, and therefore all incomes earned by the women as belonging to the men. Therefore, the concept that joint taxation or income splitting is not some sort of social engineering by tax policy ignores the long history that says that, in fact, it was deliberately designed as a way to keep economic control in the hands of men. Because Canada is a country that respects the principle of sex equality, that is not a policy that is considered to be constitutionally acceptable in democratic Canada.