annexing Gaza - won't happen because Israel already spent a lot of resources evacuating gaza and dealing with Hamas, plus the entire universe will scream "genocide".I think a three state solution or Egypt or Israel annexing Gaza with the people also having the option of becoming Palestinian citizens (whenever the West Bank becomes a country) is more realistic.
3 state solution - that would mean giving a terrorist organization a reward for committing war crimes in the form of a state. plus, that's not what Hamas is aiming for, they want a one state solution - sans Jews.
Israel was already willing to negotiate pulling out of the C territories when Ehud Olmert was PM (2007-2010), 2 wars with Hamas later - and that's not even on the table. they'll have to wait out Netanyahu's stint as PM and hope the next Israeli parliament is more center/leftist.
Egypt right now can't be bothered with anything Palestinian-y. they have their own problems.