This article is from the X-Men Comic Books FAQ, by Kate the Short (firstname.lastname@example.org) with numerous contributions by others.
No. The Malice who worked in the Marauders was some sort of pure psionic
entity who could possess people and make them into "dark versions" of
themselves. She eventually got stuck in the body of Lorna Dane by the
machinations of Mr. Sinister (UXM #239), which led to the Malice persona
eventually being zapped out of Lorna by Zaladane, the purported Queen of
the Savage Land (in UXM #250). Mr. Sinister finally destroyed this
Malice in X-Factor #105 because she had outlived her usefulness.
The Fantastic Four's Malice, who occasionally possesses Susan Richards
(the Invisible Woman), has nothing to do with Sinister's Malice. This
Malice was a mental creation by the fourth Hate-Monger and the Psycho-
Man, and it is merely the alternate personality of Sue Richards as an
"evil" person. Same idea, different approach.
However, the Vertigo that worked with the Marauders is the same Vertigo
that started out with the Savage Land Mutates. Just while we're on the
subject of Savage Land and Marauders.