I kind of like the idea of a big-ass space lobster just chilling there, but I do have a few gripes:
"Class-A amnestics are to be administered to remove memories of SCP-3485" sounds a little redundant. It's like saying, "I take sleeping pills to help me sleep."
But the lobster in the room for me is the fact that the Crab Nebula is over six thousand light-years away from Earth. This means that everything we observed took place right about when Egypt was dealing with a whole lot of bad shit coming out of the sky and a massive labor shortage in the pyramid business. This leads to two major problems.
First, all data regarding SCP-3485 is way out of date, including its current whereabouts. There is no point sending an expedition out there to try and save its life or make observations before it dies, because that already happened before a certain Indian man went on walkabout and accidentally became a god.
The second major problem is that even if the Foundation is hiding some wonderful tech from the rest of the world, that puts them maybe a century ahead of the curve. How are you planning on sending an expedition there at several thousand times the speed of light?
The way I see it, the easiest way to make the logistics work would be to piggyback onto some of the stuff established by events such as Project Heimdall. There are probably several SCPs or tales establishing FTL travel and communication if you choose to crosslink, but with no explanation there is no way to make an expedition work.