Space hulk , has a lot of options if you use the cannon that has be released so far, with that on my mind and following on a post I left at vanus temple i envision the following posibilities:
Space marines is an intruder option it will never stalk like genestealers.
Genestealers is a stalker or denizen option I don't see them in an intruder army role(O.K. it might be but with a heavy rule tweak).
Orks are orks so the will ignore any rule I can think about them and happly fight in any role
Chaos space marines can be used as intruder most of the time but against SM, only as stalker.
What do you think, are you ready to pit orks against genestealers or chaos?