I.e. is the abbreviation for the Latin "id est," meaning "that is." Another form of "for example."

He lives in PA so he has PA wages, the employer just doesn't tell you. PA taxes all compensation, so usually Medicare wages box 5. You need to enter it.

NY wages follow federal law, so box 1. Therefore, NY taxes less than PA and PA Local wages.

They might, but I highly doubt a NY employer withholds PA Local EIT.

ps NY doesn't allow "working at home in PA" in order to allocate wages outside NY state. 100% is taxable to a NY working non-resident.