" but Modo clearly has Hexagon in its sights, even if ZBrush remains unique.   Does that mean that DAZ has Luxology in its sights"

Not even close. Hex is nothing compared to Modo. I can't see a product like Modo dummy down to have Hex in it's sites.  I really doubt that Daz is looking to Luxology. It was a good deal for both companies to make some extra money and for Lux to expand to more users. Would you say Daz has thier eyes on Zbrush because of the same deal or Right Hemisphere or even Lightwave? No. They have enough to worry about with what they have now.

ZBrush and Modo would be closer but as I have only tried a Zbrush demo, I can't give an honest opinion on which is the stronger software. I would say Modo for shear power and addaptive ui with what ever combined tools you want to create. But, I don't like how Zbrush was set up so it did not fit me like modo can. So My opinion would not be the same as someone that likes using ZBrush.

Yes, anything that has some modeling tools would be better than P7 brush. Who knows, Maybe Poser will get some added modeling tools in the future. Not to far fetched whenyou think about it.