Where Can I Find A Free Auto Repair Manual Online For A 93 Oldsmobile Cutlass Cierra S?

What you heard is correct.  You can remove the calipers without disconnecting the brake lines, and likewise you can do the rear drums without opening up any lines.

You can find quite a few repair manuals at the library.  If they don't have what you need, and you're serious about doing your own maintenance, they are worth the money and will save you a lot down the road.

This is a pretty important repair you're attempting.  If you do it yourself, make sure you get good instructions and follow them to the letter.   Changing front disc brakes is pretty easy, and something that someone with average mechanical skills can do, but the rear drums take a little more skill.  If you're not 100% confident in your ability, getting a brake job at a shop actually doesn't cost that much considering this is for safety.

They sell "disc brake quiet" to spray on the back of your disc pads.  That helps retract the pad when you let off the brake and reduces the chance they get glazed.  Glazed discs are often the cause of squeeling noise if it's not due to bad pads.  You can tell the difference between glazed brakes and bad pads because hard braking will scrub the glaze off, whereas if it's metal on metal, it will continue.   

Remember Safety first.   Knowing it's done right will help you sleep better at night.