With the drowning ... I assume the plant continues to mature for several days before showing signs of oxygen starvation and death.
Would it be a good idea to submerge the roots several days before the time that you would expect the trichomes to reach the "perfect" stage (when you would normally cut the plant)?
If so, how many days do you think that the plant continues to mature for?
I'm not sure that freezing would do much good at all as it would most likely damage the plant's cell structure and pretty much kill it - too late for the plant to do anything when it is a block of frozen mush.