For the gear boxes (front and rear diffs, transfer case) the book says to fill slightly below the level of the fill hole, but most people add fluid until it starts to run out of the hole then replace the plug. Be sure you can get the (24mm) fill plug off before you remove the drain plugs. An impact socket with the outer edge/rim ground down flat (to fit closer to the plug flats) works well.
I use a 24mm "oil filter wrench" with 3/8" drive; it's a small socket and works well.
You don't say if your 80 series is locked or not but 9 quarts should do it.
Just about any GL4/5 Gear oil you find in Wally Marts will work, the generic house brand or Valvoline, 80-90 or 75-90. In SoCal you could add a heavier weight gear oil to the diffs if you wanted.
If your front diff gear oil is blackish green it's contaminated with grease sucked in from the knuckles, so you want to bypass the factory axle housing breather with just a length of hose up to the engine bay then put a small filter in the end. Zip tie it off somewhere like on a bracket out of the way.
So you could use the cheapo gear oil in the front, run it awhile, then drain it out (to help remove some of the gunk) then replace with the better gear oil. after you've bypassed the factory breather.
Don't forget the rear breather, they can get stuck open and draw in humid air into the axle housing. At a minimum replace the breather. Need to put the vehicle on a lift or remove the left rear wheel to reach the breather for the rear axle.
For engine oil, buy 8 quarts but you will use just a little less than that. Any oil brand you like but synthetic is maybe better. The most important thing however is the filter, never use generic or cheapo filters. Either Toyota filters
or some other top shelf brand (never Wix or a white box filter at the oil change shop).
Already mentioned above; the U-joints need to be regreased on a regular basis, grease monkeys will tell you they're "lifetime", they are not. Each (four) has a zerk (grease) fitting and should be regreased every 5000-7000 miles. Any name brand grease will work, take your pick, but buy a manual grease gun and learn to do it yourself, IME NO ONE ELSE will do it correctly.
The slip yolks as mentioned above (one zerk for each driveshaft) require a Moly fortified grease like the Vavloline Palladium (NAPA stores sell it)
Some people use the same grease for everything so they only need one grease gun.