I always like to look back on other comparable projects to get a grasp on timelines.
5 years ago (+ 3 days) Shanghai finished up foundation work (for the castle at least) and lifted its first piece of structural steel.
Contrast to the recent aerials. Universal does not seem to have the same marketing machine as Disney, so we might not get blog posts and videos on the date of the first piece of steel, but I'd hazard we are fairly close. Shanghai was of course plagued with build problems and pushed aggressively onwards to its June 2016 opening. I see no reason that we are not running a very similar timeframe here, with Beijing perhaps being ready for June 2021 (or maybe towards the Fall if they don't shoot themselves in the foot by committing to an opening date).
What is also worth noting: 5 years ago we had a similar flurry of Shanghai Disney leaks. I'm sure people remember the similar site layout plans as well as WDW1974's attraction lineup leak. Probably because plans were passing fast and hard amongst many contractors at this stage of the game.
The point is those leaks were accurate to the final product. As one would expect at this stage of the game. While minor variations (a Fantasyland theatre eventually housed a Frozen show) occurred, there are no drastic alterations. We likely are looking at the final product in leaks, of course entertainment is still very malleable; Waterworld can still overlay itself, but the facilities layout will be identical. The two front of the park theatre shows are clearly still working through development.
Universal has gotten very sketchy about an opening year, but I firmly believe mid-late 2021 seems like the solid bet these days. 2020 Asian products, whether they be Tokyo's expansion or Osaka's expansion are both fairly advanced in the structural components with largely completed show buildings.