I voted no, in the perhaps very foolish assumption that litigation between Eve and Jack's estate would play out in a way that reflects real life. Salem has always had its own peculiar legal system, but if the the writers stick close to reality, Eve's chances would be slim or none. What would matter are the legalities (i.e. is the contract enforceable?), not whether Eve needs the money, how much she would get, or whether the veterans deserve it more.
1) The contract relates to a sham marriage that was in essence a fraud on the Corelli estate. A court could simply refuse to enforce it on these grounds.
2) Because both Eve and Jack regarded their marriage as a sham designed to get Eve the Corelli fortune, what legitimate reason could Eve have for demanding a cut of Jack's future royalties to agree to an annulment? Thus, as Aiden noted, the contract could be regarded as extortion and therefore unenforceable.
3) How is the contract worded? If it simply states that Jack promises to pay Eve a cut of the royalties, it's unenforceable. Only contracts where both parties provide what is called "consideration" are enforceable. And if the contract doesn't specifically include posthumously-published works, a court could rule that it doesn't apply to the Afghanistan book.
Then there are the practicalities.
1) With Victor on the side of Jack's estate, it would have the best legal firepower Kiriakis money could buy.
2) Eve would be thoroughly cross-examined about the circumstances leading to the contract, convincing any jury that she's an unlikable, dishonest, lying gold digger.
3) To gain the jury's sympathy, Victor's legal team would pack the spectator area with veterans in uniform.