Standalone story so I see it as non canon and then I can accept it taking place in the ruins of the colony and we most likely will see something far out as radiated aliens or ghost aliens which I think it is.
Why far stretched: first of all the atmosphere processor thats over 1 km big in height and widht would easily nuke the colony to pieces, wouldnt be anything left, as Bishop said: the blast will be the size of Nebraska. If the colony is standing like in colonial marines or in this comic then it breaks all laws of physics.
IF so then the xenos would easily survive it, seen in earth war and their ability to survive that such things are survivable.
Also xenos dont react to radiation, like coachroaches they are unharmed by it, hence I hate colonial marines making strange mutations and new aliens due to radiation, sigh.