1) I generally use only rear panniers plus a small handlebar bag. The handlebar bag is just to keep some items conveniently at hand, not because the extra capacity is needed. The bike does handle a little better when some weight is put in front panniers, but I find it handles well enough with everything in just the rear panniers and that way I save the extra weight of a front rack and associated panniers. I currently use Nashbar's 'Waterproof Panniers' and find that they have plenty of space. I usually pack everything inside them, but if I needed more space it would be easy to put the tent/sleeping bag/pad on the top of the rack and free up pannier space. Ortliebs, Arkels, Lone Peaks, etc. are undoubtedly more durable, but so far the $30 Nashbars are holding up fine and haven't caused any problems.

2) Haven't tried a camping hammock since I've never found them comfortable to fall asleep in. YMMV on the comfort aspect, but I'd also note that, unlike backpacking, much of my bike tour camping is done in organized campgrounds which are usually set up appropriately for tents and may or may not work well for hammocks. My tent and sleeping pad together only weigh 3 lbs. and pack very small so I don't think I'd save much with a hammock/tarp setup that still protects adequately from rain and stormy weather.

3) My emergency food is generally peanut butter and jelly sandwiches that provide high-density nutrition at reasonable cost and it stores/travels well. Pasta dishes (mac/cheese, spaghetti, etc.) are also good options - I usually throw some peas or beans into the sauce for more balance.