This whole thing is too expensive, will take too long to complete, and is way too over the top of a solution to the housing crisis in HK. The government should be partaking in land reclamation throughout various areas throughout HK meanwhile continuing to release more land plots all over the New Territories including Lantau. The government should not stall its idle land policy, and should be more strict and forthcoming in getting developers to build on land that could be used for housing, or otherwise build more housing by themselves. And create more policies to ease conversion of land into housing land, but still be regulated by the government.
I believe what the CCP is trying to do is to get HK to deplete its surplus budget and treasury so that years down the line the HK government will be forced to use mainland banks to finance major projects and fall into their debt traps. That's why they propose the most ridiculous plans like the Lantau Tomorrow Vision project. Then in the future they will say oh look HK's government and budget system doesn't work, it now needs to follow the mainland system for prosperity and growth.