I'm definitely biased against believing is sasquatch in the real world, so I own by biases now by saying they're certainly affecting me even though this is a fictional world we're writing for. I just don't think this is very believable. The absurdly grand scale seems like it treads in the realm of heavy fantasy, and I've just never gotten the sense that the SCP verse wants to go there. Even if the Foundation is controlling civilian sightings to keep the truth from getting out there, and a true god like figure assisted humanity in overtaking the SCP-1000 species, is the archaeological record also being 100% monitored and controlled? Or has it just been deleted? Or are advanced technologies regularly showing up in Olduvai in the SCP universe? I just can't seem to stretch my disbelief enough for this one.
It is very nicely written though, I'll give it that.