i have a chrome hip pouch, and it can probably cater to your needs. i barely use mine (got it for free, anyway), but here's what ive gathered...

1: check. all that stuff should fit. (maybe not the book, depends on how big a book)

2: not a lot, and i dont think it'll be an issue. but then again, im a lanky giant. regardless, if its an issue while wearing your bag, you can put it in the bag...

3: seems light enough. of course, it depends on what you put in it, but if wearing your u-lock on your hip/back pocket isnt an issue, this isnt loads heavier.

4: i cant speak of the reload or seagull, but the ulock holder is a mixed blessing. i use a NY lock/chain combo, so the holster is a moot point for me. my old roommate also got one, and his mini-bulldog (i think that was it) was a hair too tiny for the one-size-fits-all holster, and was in constant danger of slipping out. also, only comes in black.

the seagull looks comparable, but a bit more expensive, although it has the outboard d-ring for keys, and multiple (3) ways of holding a ulock. also seems to have the most "features" if you need em, and is color customizable.

the reload looks a tad bigger, and i dig the buckle closure with velcro (other two are velcro only). its also color customizable. however, least amount of features, and no holster.

for a bare-essentials kinda thing, the seagull seems most versatile. take my review worth a grain of salt, seeing as how i dont have one myself, but unless someone with a seagull comes along and says to not get one, id suggest the seagull.