All available evidence suggests that cryonics is likely pseudoscience in theory and certainly pseudoscience in practice. Irreversible brain damage occurs within seconds (and total brain death within minutes) of oxygen deprivation, and freezing cell tissue in water ice permanently destroys it.
We don't really know. Cryonics avoid ice formation with cryoprotectants or via vitrification. And assuming there _is_ brain damage, in theory it's still possible to recover as long as the _information_ of the brain hasn't been destroyed. It's akin to having the mainboard and the read head of a hard disk destroyed, but having the plates intact.
What if we don't try to repair the body, but instead reconstruct it in a simulation? Even if the person's cells have all been mangled by ice crystals, a future medical team could conceivably map their neural network and estimate the strengths of the connections between neurons, with some futuristic high resolution scanning device. Maybe it doesn't matter that a frozen person is dead for now, if we could give their mind a virtual body transplant, and rehabilitate them in an idealized virtual environment.
Yeah, as pointed above nobody's using ice for ages, your information is pretty outdated. Would also help if you would support your opinion by related research on the current state of the art cryo.