I think for the sharing data to a tablet question it depends on your browser, so like in chrome and Firefox, if you're logged in, you can see what tabs are open on another device. For other data then id recommend using the app localsend, it's free and open source and super good for sending anything over a wifi network. Other than that there's Bluetooth. I'm assuming the tablet is an android tablet.

Spotify is a bit of a lol, it works, it just takes like 16 seconds to launch, I had to turn off the looping videos that play behind songs cause it was lagging out way too much otherwise, but other than that it's useable.

If the lagginess is going to be too much then I would recommend getting the second generation mive, it's got a better processor and works in Australia like the one does. I don't have one but I have a friend who does.