One of the technics that is terribly good, is not to challenge back when dealing with challenging behaviour, used a lot in restorative justice programs in secondary schools,
If you are lucky enough to have more than one adult,make sure you are operating as a tag team, if you feel yourself reacting to the provocative behaviour, swap, and keep swapping, do not be drawn into slanging matches,
locking horns with a rutting teen is always counterproductive,
part of what pushes a teen towards independence is dissatisfaction with their situation, their frustration at not being able to identify a way forward nor their ability to self analyse and articulate their issues causes them to lash out with frustration, ask any teen "what is wrong?" they rarely can be analytical or envisage a way forward, all of which frightens and frustrates them.
Asking a teen to empathise about their impact on others,is going to add to their inner turmoil, they may understand the concept, but they have yet to develop enough to implement it with sincerity,
If you can avoid being draw into their personal dramas, be matter fact about the impact of their words on you, practice responses,
"I found what you said hurtful, when you are calm I would appreciate a conversation"
If you find yourself becoming anything other than calm and neutral, explain you need to withdraw, and do so, before you explode.
I find gently when there is a lull, getting through the message that everything they do, they are doing for themselves, and to be proud of that, and to not feel overwhelmed by the enormity of the journey to where they want to be, if they just take the tiny little steps that are required each day, then one day they will look up and find themselves at their destination , teen are terrible overwhelmed about looming adulthood, part of their behaviour is panic.