Firstly, I would suggest switching to the new series with better ETS questions, these questions might not be perfect. However, I can take a look at your questions, sorry for the late reply.
Sure.
This is quite a hard question for non-native English speaker, and it’s about what the word “suggest” implies. Can you please check this thread?
It’s fine although I would be thinking more about the ideas being positive/negative rather than the blanks themselves.
I’m not sure what that means either.
Do they not convey the same idea of “something that helps”?
What would the correct “noun forms” be in your view?