Wondering if there is a way i could kill a certain companion or other "essential"NPC's,not being able to kill certain people is hurting my immersion and the person im trying to role play,anyhow any info on how to make a NPC non essential would be awesome.

If you're on PC try using http://fallout.wikia.com/wiki/Fallout_4_console_commands to set NPC to non-essential.

• setessential – Allows an NPC to be permanently killed. Click on a an NPC then enter the command for it to work. Use the resurrect command to revive them.
  • setessential 0 – Allows the NPC to be permanently killed.
  • setessential 1 – Sets them to be unkillable.

I think this'll do it

Open console. Click on the character. Write:

setessential 0

Great thanks alot guys.