None of that would happen.
Hardcore Server only needs one thing. That is resurrection turned off. The Hardcore Challenge Community will continue to use the addon on an Official Hardcore Server because that’s the type of Challenge they want to play and the players they want to play with at end game Hardcore (SSF Players).
There are a few changes that will be necessary to prevent griefing and losing potentially hundreds of hours of time investment as a Hardcore server will not have appeals.
Namely, being able to kite mobs outside of their zones to lowbie zones and have them kill players. The mobs should reset when leaving their original zone. Some bosses already work like this so it should be no problem for Blizzard to make that happen to prevent griefing on Hardcore Server.
The other is being able to attack someone when you are not PvP flagged yourself. I don’t think it should be possible to attack another player unless both players are flagged. Right now, if 1 player is flagged and 1 isnt, you can attack the flagged person on accident and flag yourself, setting you up to get ganked. This is an urgent fix as it will be easily abused on Hardcore server.