A:AnswerGoogle home and Philips bridge work seamlessly together. Most likely the same for Alexa. The bridge I operate Philips hue app and color scenes. When I am away from home I log into the Philips home app and control my lights.
A:AnswerYes, one hue bridge can control up to “50” lights and accessories. You may be able to do a few more. You can always set up a second bridge for the rest.
A:AnswerIf you get the Bluetooth one you can control the lights through you phone, using the app HueBT.
The hub will be necessary if you want it to be control it also with Google assistance or alexa.
A:Answerfrom what we gather, the bridge allows you to control the different function of the led lights. It gets hooked to you modem, we have it plugged in to the wifi extender, and can use the cell phone to control the lights