Who? If you could even just point to someone describing how this would work, that would be helpful. But I've never seen anyone actually explain how this would actually work. The only one state solutions offered is Netanyahu wanting to annex territories or nutjobs that want to ethnically cleanse (or worse) Jews from the region.
Just look at the population numbers... A one state solution would have Jewish majority. Do pro-Palestinian radicals really want a one state solution with Palestinians being a minority in a state that's majority is Jewish? There's a lot of dark intentions of those that want a one state solution. Or they just don't know what they're talking about.
Yes Hamas wants their imprisoned members released to replenish the ranks.
You do know that Yahya Sinwar was released in a previous exchange of prisoners for hostages, right? Some people claim that Israel propped up Hamas with these kinds of negotiations.
There have been a few times in this war there has been ceasefires with hostages exchanged for prisoners. Hamas eventually stops releasing hostages and the conflict resumes. The IDF ends up just fighting the Hamas fighters released causing more death and destruction.
Also Israel unilaterally withdrew from Gaza about two decades ago. But then Hamas got into power with a plurality of the vote and have been constantly attacking Israel ever since. It doesn't seem like Hamas wants sovereignty, they could have had that if they wanted it. Hamas wants violence because that's how they maintain power. Violence against Israel and violence against their own people.
You also have access to a search engine, you could use to find out what Hamas really is. They aren't freedom fighters, they're an oppressive regime that uses violence to maintain power that's propped up by Iran.
Nothing Hamas is negotiating for is for the benefit of the Palestinian people. They're only negotiating for their own interests while Palestinians suffer.