There's this City Hall Watch post that claims there are 14,000 lots. For argument's sake, take them at their word.
The eight east-side villages (Fraser, Knight, Commercial, two Nanaimo, Wales, Victoria, Kerr) are mostly 33 ft × 122 ft lots ≈ 375 m² each.
The nine west-side villages (two Macdonald, two Mackenzie, Granville/41st, Heather/33rd, two Oak, Angus/57th) are usually 50 ft frontages ≈ 560 m², with some 33-footers mixed in.
Let's assume an average lot size of ~450 m².
14,000 × ~450 m² = ~6.3 km² of developable land.
At 2.7 FSR, and assuming 1 person for every 500 sqft of built space, that would be about ~360,000 people.
You'd need to go down to 200 sqft of built space per person to get 900k people in there, or 6.75 FSR on
average with an assumption of 500 sqft per person.