My FDW has asked for Wifi password. I am not comfortable giving it as she is already on the phone all day long - I work full time, so hard to limit phone time). She has internet through her phone. What do you all do?

Since she already has internet through her phone, it does not really make a difference whether she has Wi-Fi or not. I guess trust and mutual communication is the way to go - trusting that she will fulfil her responsibilities as a worker and yourself communicating and reminding her what your expectations of her responsibilities and work ethics are.