To my understanding, all of the new streets will be public, City of Toronto roads.
However, they have not yet been 'assumed'.
That means, they are being built on what is still CAMH private property.
Only when complete, to the City's satisfaction, generally when most or all development on a new street is complete does the city 'assume' ownership.
At that time the City of Toronto will install regulation street signs.
They won't allow their (City) street sign until they assume the road for liablity reasons.
They don't want 'confusion' between private, un-assumed roads, and City roads.
This means until the City assumes ownership they are not liable for anything that goes wrong on or because of the road or its fixtures.