When lucifer or abbadon miss you, they will stop attacking. Meaning a sort of hit-and-run tactic can be used in which you hit one side and run to the other before his attack animation is completed. This gives you approximately enough time to do two attacks before he will swing again. Simply run back to the first side and repeat. Doing this I easily defeat abbadon with only snipers and taking absolutely no damage at all. This can be used against lucifer but is much harder due to his attack animation being much faster than abbadon. This isn't always the fastest way to kill them as you sacrifice every 3rd hit for running to the other side but it's certainly the safest, death free way and the easiest way to solo lucifer at a very low level.