Yes it is free!
To show you the website and items from the collection and memories from other members. It's basically a direct shortcut app that shows the site with a built in browser. Basically you will see the website.
Yes it has been tested and works very well. Do you need the app, well that is up to you as its not essential at all. I am not trying to down play the app however at the same time I am not going to over sell it as the app is basically the website. It's up to you if you wish to have it on your device.
Nope, as I said before, it's an app showcasing my website including this very page.
It should self update to the current website design however, every now and then I will update the app on here.