The searching for DNA in the soil is a long shot but if that Neanderthal DNA was identified it is worth it to try this. However the conditions for preservation of DNA on Niku are much worse than in dark cool cave. Heat and UV light are very bad for DNA . This quote is from a review of forensic DNA recovery,admittedly it is from2004 and techniques have improved greatly since then.
"The results obtained from the analysis of DNA from ancient human bone tissue, horse bones, and mummified soft tissues (from 40 years to 50,000 years old), indicate that all samples with low levels of damage and from which the DNA could be amplified originated from regions where low temperatures have prevailed throughout the burial period of the specimens.29,33"
While it was very cool to hear that all the cadaver dogs selected the same depression near the Ren tree what does it mean for the Niku hypothesis. In my opinion it confirms the quality of the work of previous expeditions in identifying the seven site and eliminates any reasonable doubt that the seven site is also the bones site. That is important as many of the most significant artefacts have been found there and tying the bones and artefacts together gives a more complete picture but it doesn't advance efforts to prove it was AE or FN who died there. Hopefully DNA can be found that would do this.