Sefer Chofetz Chaim Chapter 2, halacha 2, rest of note 3

This week we wrapped up foot note 3 about the Gemaras in Bava Basra and Erechin which deals with the laws of apei tlasa. In the end we saw 5 views: 
1: Rashbam who says the speaker gets a sin for speaking lashon hara but those that heard amongst at least 3 people could repeat it since word spreads anyways.

 2: Tosfos says neither the speaker or listeners can speak out right lashon hara even in front of at least 3 people but avak lashon hara, which can be taken in two ways, as long as it has a positive slant is permissible to be said and repeated. 

3. The Rambam says that though lashon hara can’t be spoken but if heard in a crowd of at least 3 If it is repeated as long as one does not have the intent to spread it, he does not get a sin. 

4. Rabbeinu Yona says that one can spread the news to at least 3 at a time of a person who harmed another person, as long as all the rules of permissibility are met, which are discussed later on in Sefer Chofetz Chaim. Then others can spread the news to protect others from harm.

5. Rashi in Erechin seems to be saying that the case is when someone talks about his own business, good or bad or his own wrongdoings which normally should be kept a secret if divulged in front of one or two people but if said in a group of at least 3 he indicates that he does not care for the word to spread so other people can then go and spread the news. 
The Chofetz Chaim clearly indicates that none of this negative talk is allowed to be accepted, one can only take proper precautions when necessary, even if it is permissible to spread. He concludes that it would seem that this flexibility is very complex and practically uncommon so one should be very cautious to rely on it as will be enumerated further in the rest of the chapter.