I've no idea how I'll do on this quiz. Let's find out:

From the quotes:
1 Short, yet telling, at least as to story. It's got to be Aussie Rules, by Female Hawk. I don't recall who said the quote. If it weren't for the quiz category, I'd have guessed the character to be Lois "Flinders" Lane. As it is, I'll guess her boss...Hmmm...I'm awful with names, but I think his nickname may have been Blacky. (Or Browny, or some such dark colour. *sigh* I'll stick with Blacky.)
2 ?
3 IIRC, Sam played Jonathan, and both were excellent players. Unfortunately, that doesn't get me any points.
4 ?
5 ? Hawthorn? So much for "arvo" being the Big Tell in #1. You are right -- you are being tricky in this! OK. So I'll guess "Aussie Rules" by Female Hawk with Blacky speaking for #5.
6 ?
7 I immediately recognized this as The Gifts by me, and was puzzled about who the original or supporting character could be, and then I laughed when I remembered that I wrote Tank into the story. And I know who said the quote: Clark. So I guess the quotes are not necessarily by the original/supporting characters. I'll keep that in mind for the rest of the quiz.
8 Eye in the Sky by Saori nee Tanaka?
9 I'm pretty sure this is Inspector Henderson speaking in Inspector Bigmouth, by anonpip
10 ?
11 ?
12 ?

Hmmm. I didn't do very well with the quotes. Let's try the excerpts. If not included, my excerpt answer is the same as my quote answer:
1 All right. This sure sounds like Aussie Rules again. Could this be part of the trick -- you listed the same story twice.
4 I tend not to read New Krypton stories, so I'll guess a story I haven't read; Different Directions by LaraMoon
6 Clasicalla's Bats!, and the vampire in question is none other than the Batman himself, Bruce Wayne. (Do we need to identify which version of Bats!? If so, I'll guess Version One, but I *think* the excerpt is common to both versions.)
12 The Time Traveller's Wife, by ML Thompson

I'd rate my performance on this quiz as fair to middlin. I'm curious about how well others do on it.

This was an exceptionally fun quiz. Thanks for writing it, Nancy!

Joy,
Lynn