A:AnswerNo, you should be okay.
Take for example:
If the HDMI cord fits your cable box to your tv, then just take the HDMI cord from the cable box, and plug that into your new gaming PC, and score!
A:AnswerI can’t really say how much you will lose with it being that long . But if you don’t use a good one you see snow . As in old TVs . Snow is ok if you want to take a nap .
A:AnswerUnless your LG phone has an HDMI port which I'm guessing it does not no you can not hook your tv up. You would need somthing such as chrome cast to be able to link your tv with your phone.
A:AnswerNot if the TV is not a 4K unit. Regular HDMI will work great. If you are using an antenna, HDMI is not needed at all unless you are connecting a DVD or something.