Few vs. Only a few and combining necessary terms with same sufficient

Hello, I have two questions. Q1. I saw that few means some. But why does only a few, only a minority, only some turn into a 'some do and a most don't'? Questions 18, 23, and 24 all do this. Can you please explain why it is not just a some statement and why we can assume the negation (most don't)? Q2. I also saw that some questions with the same sufficient condition end up combining the necessary conditions as an "and" statement. So if there are three statements then would they be able to be combined? For example: A->B A->C A->D = A-> B and C and D? Or would it just be a combination of some statements (B-some-C; B-some-D; C-some-D)? Also, would the we be able to combine the statements with the same necessary conditions with an "or" statement? For example, A->B C->B = A or C-> B?