Well...
based on part of the reasoning why Marvel doesn't play too much into religious matters.
Galactus can consume both Heaven and Hell, so I don't see why he couldn't handle Lucifer.
I just considered what would happen if both universes merged, and what an abstracts role would be...
Balance has to be there. Of course Balance can be...tipped at times, but I don't see Lucifer Morningstar outright negating the aspect of balance in a continuity.
Although...it could happen, that's why I say 6-7/10. And yeah, I understand that the way DC wrote it, it was portrayed as them being the first creations and all but still.