Wanted to clarify that in some provinces child will be covered by provincial health insurance so would verify the eligibility requirements for the province where you intend on settling before purchasing emergency travel medical insurance.
Not contradicting this point but as a small addition to keep in mind: currently provinces can also have slightly different periods in which the provincial coverage takes effect (typically either three months or immediate), plus the question of whether one can get the paperwork filed immediately or in what period. (Coverage may be immediate from date of presenting paperwork or back-dated to arrival, but ... unpleasant to have to deal with that in event of an urgent issue).
Which is to say: emergency travel insurance at least for a short period (eg one to three months) for a young child may still be a good idea.
On the other side, 'routine' doctor's consultation at a walk-in clinic may be out of pocket, but at least not outrageously priced. (IMO).