Only if they are available digitally (no DVD slot for Wii U discs) and only if Nintendo offers some digital game transfer program like they did between the Wii and the Wii U (digital games are tied to your console, not an account)

Older titles via emulation maybe, but it has no backwards compatibility with DS games nor Wii/WiiU games.

Switch takes new cartridges.

The Wii U is a faster Wii (from a hardware point of view), basically same CPU architecture, just more cores and higher clock speed.

The Switch runs on an ARM CPU. I doubt it will be compatible in any way.

Why would you assume that wii u titles would work? The switch only takes cartridges, virtual console titles are already tied to the console and don't even carry between wiiu systems, and the switch uses an nvidia tegra (arm) architecture where as the wiiu uses powerpc and an AMD graphics chip.

Not even the wiiu controllers will work with the switch.

Zelda and "1 2 Switch" are the only real launch titles, there's some filler crap to be sure but no one cares.

Skyrim is not a launch title.