A:AnswerYou will need one cable from each peripheral (2 for you). But note that your DVD player might not have HDMI. It might require component or composite cables.
A:AnswerYou can wall mount the unit, or it has two legs for mounting on a table top. It is not made for ceiling mounting. I guess you could rig something up as it has the industry standard mounting screws. It might get in the way of your mirrors.
A:AnswerYes there are 3 HDMI inputs and I have the chromecast which is similar to ROKU and Amazon stick. They basically turn the TV into a smart TV for a fraction of the cost