entered my first comp this summer (iowa state fair). entered 4 beers (blonde, foreign extra stout, old ale, american IPA). got one 1st (the stout) and the blonde and IPA were both one point out of 3rd place and finished 4th. the old ale was 2 points out of third and finished 5th. very happy with the results.
as far as what to include, i'm pretty sure you just want the category and nothing much else. you should have knowledgeable judges who only need to know the category they are judging. it doesn't matter if it's outside guidelines, they will judge it as they can best determine. my foreign extra stout is technically speaking a russian imperial stout, but i knew it wasn't "big" enough to do well in the RIS category, so I entered it as FES and it scored a 39. i haven't gotten the sheets back yet, but look forward to the feedback for sure.
i would also recommend entering as many beers as you have available (as long as they're not really bad), it typically doesn't cost TOO much to enter a beer and the feedback should be very helpful. and even if you have drank too much of a specific beer and picked it totally apart, that doesn't necessarily mean a judge will agree with you and they might find your beer a good example of the style.