Let's see if they'll alienate the market or make good entry.
4 SKUs? I'm going to go with alienate it. This is a similar problem Steam Box faced. Instead of a nice simple launch, they had multiple SKUs by different manufacturers. I mean, retailers are going to have to take a stinking course just to know the differences. Good luck passing that info on to your average consumer. And then there will be a simple $399 PS5 SKU sitting next to all that confusion. I think most would just say screw it and grab the PS5.
Also, the OP mentions Navi for the XB2. I'm thinking they may have to go with Vega. If AMD is truly working as closely with Sony in creating at least the first round of Navi GPUs as insiders have stated, I just don't see Sony being fine with them handing that tech right over to their competitors. I would think Sony would have a console exclusivity agreement on that for at least a year or two.