Suspiria had lots of super-powered Ocampa for friends, who would have objections to Seska killing Suspiria and having her way. So, no.
The Ferengi had money, a ship, possible exchange value as prisoners, and, at the very least, offered a distraction, all of which would have been attractive to Seska in plotting her getaway on return to Federation space. So, no, Seska would also have engaged with the Ferengi, albeit for different purposes. But I suppose you could rebut that Seska was a better villain than the Ferengi, and would have won instead. So, maybe.
I guess that's why people curse Voyager's wasted potential, it could have been just three seasons instead of seven.