People expecting a 2016 launch are crazy. Third party devs would be furious, these dev kits are likely going to be change numerous times before launch. Anyway, here's kind of what I'm expecting.
Handheld and console are two seperate things with shared architecture and OS. This allows games to be easily ported from one to another without necessarily having to be available on both.
Cross-buy will happen, but not on the scale people are expecting. I think there will still be exclusive games on each system (even first party) but having both gives a game extra functionality. For example, imagine a Pokemon game for the handheld you could then connect to the home console and get some kind of Pokemon stadium like experience for no extra cost. Third party devs will have the option to do cross-buy, VC will be cross-buy, but I don't think Nintendo is going to ditch the opportunity to sell the same game twice. Maybe offer discounts if both versions are purchased on eshop?
Neither will be super competitive spec wise, likely both run some sort of ARM CPU. I think Nintendo really needs to target a good price again, no more than $300 at launch for a console, no more than $200 for the handheld.
Handheld will launch first, but not much ahead. I expect summer 2017 for the handheld and holiday 2017 for the console.