You mean "579 N.E.2d 873, ___ (Ill. 1991)."
Incorrect. You need a period after Ill, and no comma after Ill.
Argh. Yes and yes, thank you and thank you. (The comma was a typo.)
Depends on the purpose of the document, generally this is good advice, but it really depends. I've had to put documents into state courts that specified state citations. However, given the OP's apparent level of knowledge, this is probably for some 1L assignment, so yes, the regional reporter is appropriate probably.
This is a fair point. My answer was based on the title of the thread "Quick Bluebook Question." Hewing to the Bluebook, you cite to the regional reporter. But you are right, sometimes it's appropriate to deviate from the Bluebook.
Also, Cisarik, 570 N.E.2d at ___. would work. There isn't one correct way to do a short cite, and typically including the case name is a better alternative. Rule 10.9(a)(i).
Also a fair point, although it should be
Cisarik. My answers (without
Cisarik) were based on
Cisarik being mentioned in the sentence preceding the cite.