Aircraft owner automatically accepts liability and his insurance pays out. However, I would imagine that should there be indication that there were other factors involved, then the insurance company will make a claim on the other 3rd parties insurance policy.
With regard to the consultation, my understanding is that the AAIB complete a Final draft copy which is then sent to each individual (or their representatives) and also any person/s or organisations whose reputation n may be adversely affected by the findings. They then have 28 days to make representation before the finalised report is completed and published.
Therefore, it would appear according to reports in the media that one party has asked for an extension to this timescale presumably to provide additional information or seek further advice.
However, in view of the fact that the prelim inquest hearing is scheduled in March I think the AAIB should now say to the party you have had enough time now. They can always make amendments after, as this has happened before, if it really needs to be done.
With regard to the police investigation I expect the are stuck in limbo too, as they have no further leads to follow until the AAIB report is published as this will contain all the other facts such as expert calculations, condition of aircraft etc that they have not been able to access.