Flying Pan's also breakfast only, so no onion rings or cheese fries if that's what you're looking for. Great omelettes and eggs benedict though.
1. Agave in Wan Chai's probably your best bet, but it's not quite like the Mexican you have in the US. See all the mexican food threads for an idea.
2. There are bagel stores in Soho, might be decent, haven't really tried myself. The few NY Style delis in Hong Kong (Main St. Deli and Archie B's) have bagels, but frozen. Really, coming from NYC, you're bound to be disappointed no matter what.
3. Big Ernie's Diner in Wan Chai's got ok diner food. There's one in LKF too but both are pretty pricy. The other option is pub grub which these days is pretty similar.
4. No real places that do fried chicken here. KFC is the only popular place and I don't know of any other outlets for it.
5. same with mac and cheese, though if you really want it, it's not that hard to make at home. 
6. Best pizza's a tough question, you're going to get different responses across the board. Nobody here does NYC style pizza, and just like the bagels, it's best to lower your expectations. Wildfire's OK, and the Italian restaurants here make very good, genuine pizza, just so long as you're not looking for NYC sizes.
7. What kind of BBQ? A few places offer grilled selections. NOBODY in HK offers real, KC barbeque. Nothing smoked, nothing slow-cooked.
8. This is where I think HK has NYC beat, IMHO. Plenty of middle-eastern places in HK, mostly around Central and Soho. Beirut in LKF has the best hummus, Beyrouth in Soho has the best shwarmas and sujuks. Habibi or Bazaar for Koshary, Sahara or Marouche if you want to have some shisha with your meal.