The facehugger disparity is annoying in A3, assembly cut. You can see it's a regular facehugger in the credits, yet the facehugger in the Ox scene is the Queen. Different colours. So, in the assembly cut I guess you have to assume that there are two facehuggers. The regular impregnates Ripley, the Queen impregnates the Ox. Otherwise, a regular facehugger caused the Sulaco fire, impregnated Ripley, became a Queen 'hugger, impregnated an Ox, then died.