A:AnswerIf you have a devise without WIFI connectivity, but has a ethernet port (J45 cable port), yes, this is exactly what you need. I never try it on cellphone hotspot, so not sure if it works on cellphone hotspot.
A:AnswerNo, this particular Wi-Fi extender does not have an Access Point mode like some other model Wi-Fi extenders do and depending on how much distance you're hoping to increase your Wi-Fi signal by, this model may or may not accomplish that wirelessly. Since you already have an ethernet cable from your router to the area where you need it your best bet would be to get an extender that offers an Access Point mode.