A:AnswerThe Brother HLL3290CDW will only connect to the 2.4 GHz wireless band. The Brother machine will not "see" or connect to the 5 GHz band of your router.
A:AnswerYes. I have done it This printer has a single USB interface. You probably could connect it to multiple computers via a USB hub but I have only used a single computer connection. But it also has a built in wireless interface. You have to go through the setup to get it connected to your home wireless network (pretty easy). Multiple systems on your home network such as cell phone and laptop can print with no problem.