Looking to fly CX829 next week, and I've been checking days from July 30,31 and Aug 1. On Cathay website, it looks like there are hardly any seats on Mon and Tues, and a couple available on Wed.

But on Expertflyer, I am seeing that many of the seats like labelled "Premium" or "Blocked".
Can someone please explain how this works on CX? I've found a couple of threads here and there, and the usual answer is related to Bassinets being blocked. But surely not 1/2 the J cabin?

Will Blocked or Premium seats be bookable by MPC GO or above?
Are these similar to "Preferred" seats?