Mission: Kill the Joker
Every time the Joker is captured, Batman lets him live to escape and kill again another day. The residents of Gotham have finally said "Enough!" Pooling their funds, they put out a contract for a hit: whoever kills the Joker will receive a cool $100m. They have 1 month to locate Joker and carry out the hit.
A number of assassins and mercs answer the call:
1) Deathstroke
2) Wolverine
3) Hand Ninja Death Squad (10 Hand Ninja)
4) Deadpool
5) Gambit
6) Taskmaster
7) Elektra
8) Punisher
9) Lady Shiva
10) Lobo
Easy scenario:
Joker is unaware of the contract and Batman is in space with the JLA.
Medium scenario:
Joker knows the contract is out, but Batman is still in space.
Hard scenario:
Joker knows about the contract and Batman is back, determined to stop anyone carrying out the contract in "his city".
Joker can't leave Gotham, and nobody can bring in outside help (JLA, Batman family, Injustice Society etc.). Standard resources only.
Each assassin is a separate scenario i.e. they are not competing.
Which of the 10 could succeed in pulling off the hit?