All the bookstores in the US have coffee bars and free Wi-Fi. At least in my town they do.
It’s OK but too many kids sitting around in the book isles reading. I sometimes step on them and act like I don’t see them! It’s better to have the coffee bar in a separate building and then have a shared courtyard or something. If not, you’d have people spilling coffee everywhere and a lot of people just hanging out to be trendy!
Good Luck with the bar.