With regard to your facts:
1. Correct. Tiger cheated. He either a) did it intentionally or b)proceeded under the wrong rule/ wrong interpretation of the rule. His later comments indicate that he interpreted the rule wrong. He should have received a 2 stroke penalty at that time, because...
2. Ambiguous or not, dropping 2-4 yards away from the spot you can definitively identify as your previous shot does not qualify under any definition of nearest.
3. The committee never got anything right. They should have given him a two stroke penalty before he signed his scorecard. When Tiger acknowledged that he applied the rule incorrectly / applied the incorrect rule, the committee should have stepped in and said "sorry Tiger, even if you didn't intend to cheat at the time, you applied the wrong rule and the USGA previously ruled that ignorance of a rule is not sufficient to waive a DQ. You acknowledge in your post that Tiger must have been ignorant of the rule, because he wouldn't have talked about it if he intentionally cheated. Again, ignorance cannot waive a DQ. The USGA and R & A have been very clear about this. The Committee has zero discretion as to that matter.
Tiger's only saving grace was the Committee's failure to assess the two shot penalty initially. If they told him "Tiger, you are good to go", and nothing else happened, then I could see not DQing him. However, once new evidence came to light, namely Tiger's admission of guilt, the Committee had sufficient grounds to amend their ruling. Some people say that Tiger should have been able to amend his scorecard since it was the Committee's mistake in not applying the penalty. I don't buy that. When it was obvious that he cheated, he was coming before the Committee with unclean hands and was in no position to argue equity.
Tiger got a benefit of the doubt that no other golfer outside of Phil or Rory would get...then he put his foot in his mouth. It is rare that a pro golfer intentionally cheats. However, if he signs an incorrect scorecard and then admits to applying the wrong rule, he must be DQed. If, on the other hand a golfer doesn't, for example, see his ball move and then some asshole calls in after the round and reports it, the HD rule kicks in because that is ignorance of fact. There is a HUGE distinction between ignorance of fact and ignorance of law/rules. Tiger was the latter.