jis/iso has nothing to do with being a low end bike. it's the square taper in the crank arms. generally japanese cranks will be jis. italian cranks will be iso. there are high end cranks in both standards, there are low end cranks in both.

all that matters is you match a jis bb to jis cranks and iso to iso.

tools required:

1) hex key to pull the crank arm bolts (it'll be 6 or 8mm)
2) square taper crank arm puller
3) cup spanner (i can't remember i think it's 32mm)
4) hook spanner (for the lockring)
5) pin spanner (to hold the cup while you tighten the lockring)

really the plastic sleeve isn't a requirement. the cup wrench is a requirement to put the drive side cup on and tighten to spec. i see people try and do this with a shifter instead, which generally just scars the cup.

the only other things to be careful of the first time you install, most people tend to over tighten the non-drive side cup, which side loads the bearings. you're better off having a tiny bit of play than side loading. also the bearings are directional - i've seen people put them in backwards, so make sure you've got them in the right way.

personally i've never worked on a 'fixie' so don't know how people tend to lube the bearings. i work on a lot of track bikes which don't get ridden in the wet, and get broken down and rebuilt frequently so we tend to use very light oil in the bearings. i suspect if your riding outside, and servicing infrequently, you'll want to use a heavier grease in there.