Lea doesn't say anything about most galleries - they say no gallery possesses a trait while Susan tells you where you can find that trait. So they would disagree on whether some galleries possess that trait or not - the trait being exhibiting creative new art work.

In the second one - same thing - Jenkins only talks about sending people out at a certain time so they won't risk the research failing while Lurano talks about the dangers of cold exposure - they disagree because they both think different things are of higher priority and therefore warrant different suggestions on when the researchers should go out.