How many of them are Microsoft published, and how many of them are cross-platform?

Sorry, no idea. I don't really see what the difference is from user perspective either way (as long as the feature is compatible with the underlying hardware).

My experience is that of a bystander with fairly high standards none the less. My kids seem to love Skylanders, Disney Infinity and Plants vs Zombies Garden warfare local multiplayer on Xbox one and what I observe works great.

Those ones do, but the games for which this is true are increasingly rare. It's no longer an assumption with multiplayer games.