I've just bought the Fuji kit; haven't tried it yet but I can answer some of the above questions from the instructions:
- it's designed to be re-used, giving 80 rolls (120/135) of capacity from the 5L kit
- mixing ought to be just a matter of syringes of concentrate into bottles of waters, I've seen references to people making up 0.5-1L (8-16 rolls worth) at a time
- mixed developer keeping time in full stoppered bottles is stated as 8 weeks, less (6 weeks) in floating-lid tanks
- bleach & fix should last for a year or more

I bought mine from Ag Photographic in the UK and I'm in AU so the shipping cost (along with lots of paper) sucked. Ought to be no more difficult to get it to the US than it is to here.