Not just commercial landlord social housing; it applies to the whole local council area. Just to give you a generally applicable example, i.e. when the local council want to build up a certain area that used to be problematic area (high crime rate etc), they increase the requirements to move there, thus making it more difficult to move there. Those who wants to register there need to already secure employment and show that they are favourable tenants economically.

No. I assume you are a local citizen so you won't have to experience this kind of situation.

For my specific situation, I straight away move in apply to register for the first time once there. I follow the local council regulation. There's nothing illegal in there. But as a non-EUs it's more complicated because need to get a local bank account, prove of employment (contract) etc. If we can't meet the full criteria, there won't simply complete the registration. So, yes as you wrote before, we can register post moving. But no, when we apply to register, it doesn't mean the registration can be completed smoothly.

Just Google and compare the process to move in to The Netherlands to other counries. I'll be very skeptical if someone said that in the Netherlands the process is easy.