The Landing Bay is basically an endless level for now, just so there’s something to do while waiting for me to actually finish it
I thought so - there's no percentage over the Landing Bay, so I figured it's either unfinished, or I had to do the new investigations to properly unlock the boss (haven't done them yet since the new update), but I'm pretty sure the investigation is unrelated to the Landing Bay (more to do with the Black Market, obviously).
Other than the investigation, I'm basically done with the existing content already (loving the Pump City sermons idea!)