Xbox series X questions

howdy folks. like probably most of you, im super duper keen for the next generation of consoles, and i have just realised that im not entirely sure on what can, and can not be done. some of the questions that have come to mind are a couple of the following.

1. will my headset for my xbox one, be compatible with the xbox series s/x console, or will i have to go out and acquire a new headset.

2. will i still be able to communicate with my friends who have not gotten one of the newer consoles, while i am on the series s/x, for example will i be able to join parties with someone on an xbox one, while i am on a series s/x.

3. will my hard-drive that i use currently for my xbox one, be compatible with the new generation of consoles, giving me access to the games that i have downloaded and am currently using, on the new generation consoles.

if you also have more questions, and im sure some of you do, feel free to ask them, and lets see if we can get any answers from microsoft, so we can get ready properly for the new line of consoles which we have been looking forward to for so long

:)