With just 11 days left to the month, I doubt very much that any employees are moving into the main building this month. Employees may start moving in in May, but there's tons of work left to do. Just getting the construction equipment off of the site would take several weeks. I bet it would take days just to get that orange safety netting off the top of the building. All those very large cartons sitting inside the building must be office modules and the like. All of that has to be put together. This place is huge. Lots of work still to do and the place will need to be cleaned top to bottom to get rid of construction dust before employees move in.
And I don't know specifically what California's laws are, but I would assume the place needs a certificate of occupancy. I can't see the authorities granting that until most of that interior space is cleared of construction and packaging debris.
All of these videos have shown very light traffic on the highways, so I assume they're shot on Sundays, probably early Sunday mornings. And so we also see relatively few construction workers. Anyone familiar with the site during the week? Are there a thousand construction workers there? Because it seems to me that's what it would take to get it ready for move-in if it's happening before June.
From the looks of the night time shots where you could see inside really well, you're right, they're not going to be moving into the doughnut building by the end of April. However, the rectangular R&D building looked like it was move-in ready. The office desks looked to be in place. I think that's where they'll be moving into this month. They probably have a COO, for that building only at this point.