All phrases in section 1 are technically valid, but some are worded a bit awkwardly. I will assume you mean to say "unhappy", not "unfriendly", at the end of 1b and 1c. 1a has the meaning of 1d and 1e, because it's speaking a bit figuratively. It not does have the meaning of 1b and 1c, although it appears to. To elaborate, 1b and 1c point to a specific moment in time. 1a uses language to suggest it's pointing to a specific moment in time, but in reality, it is not. In 1a, the "when" is intended to mean "when he knows", which makes it mean something like "if", not "at the time". 2b - I will say this sentence is wrong grammar, because "That we talked" means "The fact that we talked" which is referring to something completed in the past, while "might" refers to potential future, so these two parts of the sentence don't match. 2d - I will say this sentence has a very minor but certain mistake, because "might help for us" is bad grammar - it could be corrected by changing it to "might help us" or "might be of help for/to us". 2e has a different meaning, because "would" means "definitely will", which implies certainty, where as "might" implies uncertainly, ie, "we don't know if it will help, but it might". 2g - I will say "for us for us" should have a comma, as in "for us, for us". But this is debatable. Nobody will disagree that the comma is helpful here, but some people may say your version is still technically permissible. Personally, I'm on the fence about whether or not it's a strict violation of grammatical rules - I'm going to say it probably is, due to how much it looks like a mistaken repetition when not spoken with a pause or written with a comma. 2h has a different meaning because it is talking about only "you" talking to Dean (don't forget to capitalise Dean). While 2a is talking about all of "us" ("we") talking to Dean.