Guillaume:
Sometimes we (as TD's) try to overthink a situation. Stick with the basic fundamental rules of etiquette TDA #58 A penalty may be invoked if a player exposes any card with action pending....
TDA #59: No Disclosure: Players are obligated to protect other players in the tournament at all times. Therefore players in a hand or not, may not: #1 Disclose contents of live or folded hands.
Getting back to your question #15. I thought that the floor made the correct decision by allowing Player B to retract his raise because too much information was given to the other players that had not yet acted. Remember, there are times when unusual situations occur and "protecting" the non-offender is the best solution.
What I don't like in these situations; is when we decide to evaluate the contents of the players hands, and try to figure if they should or shouldn't act the way they did. Most of the time, the contents of the players hands should be irrelevant! I questioned why Player C would fold his three queens with two cards yet to come...this is wrong. His exposing the cards is the issue.
Players must abide by the simple rules, and it's your duty to see that they do. Whether it's a casino environment, or a house tournament, players can not disclose the content of their hands until showdown. Repeat offenders will lose their welcome to return. I like the way your situation was handled.