Hi Matti, the best adhesive would be the 3M Scotch Restickable Dot. You can find it on Amazon and also in Office Depots. It's reusable and washable

I think the easiest would be to just set up a http server on your computer and then use the Internet Request action on the Flic hub. Then your http server can then further make osc requests or whatever when a button event is received.

Yes, after initial setup of hub using phone, you don't need the phone.