We know that WY puts a ton of value on acquiring a Xenomorph for their weapons division.
But purchasing a whole new space station seems incredibly expensive, especially since the only thing they would have known is that a salvage team had acquired the flight recorder from the Nostromo. They would have gotten the flight recorder anyway, as well as the coordinates for the Engineer crash site where all the eggs were originally found since Marlow found it by "extrapolating the path of the flight recorder".
We know the reason they bought Sevastopol was to reprogram Apollo, but I feel like this move would only be worth the investment if they already knew the Xenomorph was on the station, which I think would make reprogramming Apollo very difficult.
Did Weyland-Yutani purchase the Sevastopol before or after the arrival of the Xenomorph? If after, is it stated who reprogrammed Apollo and if they made it off the station?