Dan o Bannon and Ron Shusset given writer credits for Alien 5

I would say that this confirms the presence of Ripley, which would be fair acknowledgement imo. So there is definitely no mistake about mentioning O’Bannon and Shusset.

The bigger question on my mind would be that since Alien was originally rooted in Dark Star and Star Beast, could there be ideas based on these. It would be interesting if it ever turned out that Blomkamp had got to meet Dan O’Bannon and swap notes at some time in the past.

Didn't they also give Dan O'Bannon credit for AVP? I think it's just a courtesy because the movies are based on his creation.