Get students to list some possible solutions to each student/problem (examples corresponding to the situations above follow):
defer to office hours, after section, email. then if they actually follow up (which they usually don't), maybe give them some websites or papers or books to read, or maybe even an extra credit project (if that's what they're looking for and if that's OK with your Prof and Head GSI). if they feel Ay 10 is too easy, suggest switching to Ay 7A?
same as above.
defer to office hours, after section, email. try to (briefly) convince everyone that percentage-wise, the 50th decimal place doesn't matter EVER! give the student some calculations to work out figuring out how big a difference these “errors” actually make in the final answer of a problem (i.e. their calculator isn't nearly that accurate).
you should be doing a variety of types of work (group, worksheets, lecture, etc.) and not everyone will like all types, but hopefully all students will have SOME PART that they like and find useful. if they really just don't want to be there, remind them that they can leave at any time…but they will fail the Section Grade (however many points that might be for your version of Ay 10). (Holly Maness has a policy that students who never show up receive a bad-but-nonzero section grade, while those who show up and are disruptive receive a zero. The idea is that everyone is better off if such students just aren't in the room, rather than if they're in the room and causing problems.) Point out to them that they'll get a chance to express their opinions fully and anonymously on a mid-semester evaluation and if many students agree on something, the section can certainly be changed for the rest of the semester.
similar to above, again, this stuff shouldn't take up much section time, so defer to office hours, email or after section time.