1. The money it would take to sign up for cryonics, though not large, is enough to buy several centuries of healthy life each year if given to givewell's top malaria charities.

I don't see the point of extending the lives of people in chronically dysfunctional societies which can't solve their own malaria problems. For one thing, the boys who survive could just wind up as soldiers for the local warlord and make other people's lives less desirable as as consequence. For example, they might wind up raping the young women who survive.

1. There is a chance we'll discover immortality in my lifetime.

Sorry, this shows seriously confused thinking. You can't test the effectiveness of "life extension," "anti-aging" and "immortality" treatments on humans any faster than the rate at which humans happen to live. We can conduct experiments to create mice which arguably live the muscine equivalent of 1,000 human years. But we know the results of these experiments because the experimental populations have already died with recorded birth and death dates for each individual mouse. But we can't extrapolate this to humans because you can't tell if someone can live 1,000 years until someone lives 1,000 years, which means we will won't have that knowledge any faster than it can arrive.