I can't answer your questions exactly, but here's some idea, might be able to find specifics elsewhere:
1. Not sure.
2. Same as above, but there are apps that can either hide or lock apps - if rooted and running Xposed, something called MinMin Lock would allow you to pin protect apps.
3. Erm, you can probably guess what I'll say
Never used the multiple user feature on any android device - so I guess your suggestion would work?
4. I think not, both devices would just sign in with your one Google account, so you can download from 'My Apps' in the store.
The process requires you to 'root' the device - a risky process that could turn your Hudl into an expensive paper weight. There's a guide out there, with some peoples accounts of how it went.
Rather than root, you could just install a different Launcher (Nova maybe) - then use that to hide the Tesco apps, and replace the Tesco launcher.