I'm not one of these kids but I am sympathetic to them. Here's my best stab at how they'd probably react to these points you've raised.
1) Do you think Trump would be better for Palestinians? Have you looked at his record and his statements on the matter? Do you not see at least some contrast between Trump and Biden?
2) If not, what's the plan to free Gaza if Trump gets into office?
They genuinely believe the Israeli invasion of Gaza constitutes a genocide. If you truly believe that, there is no such thing as a lesser evil. Thus, these questions make no sense.
3) Also, what's the plan for LGBTQ rights, student loan forgiveness, climate change and other priorities that will surely move backward if Trump wins?
Again, they are aware Trump will be worse than Biden on many issues. They simply cannot countenance voting for someone they genuinely believe is aiding and abetting a genocide.
4) How will you navigate a Democratic Party that will likely blame you heavily for Trump's win and won't consider you a good faith partner in shared objectives?
I would not take it as a given that the bulk of the protesters consider themselves Democrats. A great many of them are or will gravitate towards the sectarian far left (think minor communist parties and anarchist collectives). A lot of them are young enough to have never voted before, and if they do vote this year they'll vote for Jill Stein or whoever the PSL nominated.
They don't care what Democrats think about them and do not intend to "navigate" the party in the future.