From what we do know, it's actually very reasonable. We know e.g. that memory survives hypothermic loss of electrical activity. So it is probably structurally based.
Not at all what was said. In fact, the whole criticism you linked to is about structure, and ways in which it is supposedly altered beyond repair. The notion that we are transient electric fields that fade the moment the brainwave goes flat is long discredited.
No! That's not at all reasonable. We understand very little about brains. We understand even less about deep-frozen brains.