What tools do I absolutely need to replace brake cables?
Fourth hand cable stretcher - I think this is one tool I'll need to get, or something similar. I see Pedro's makes a version of it, I'm not sure if it's made as solidly or not. What should I look for when buying one of these? 


Never found I needed one, typically I pull the inner brake cable as far as possible then close the brake calipers all the way (i.e., engage to the rim/disc), then attach the cable. Usually, I missed a bit of slack pulling by hand, which is taken up by the caliper return spring. You may need to repeat a couple times to get everything settled.


  Cutter pliers I have a couple of similar cutting pliers, I don't think I need to get another one. Or is there something special about these? 


If you have cutting pliers that could cleanly cut shifter inner cabling, then you are probably fine.


  Cable housing cutter - Looks to me like this is a fancy wire stripper. Is there anything about brake housing cables that I need to know that would make using a sharp wire stripper problematic? 


This is the only item on your list I found invaluable, bit it depends on the quality of brake cable housing you intend to.  If you already have cutters that can cleanly cut shifter cable housing then this will likely work on regular brake cable housing that uses a coiled construction.  If you are using "compressionless" brake housing, then only the best of the best cutters can make a clean cut.  

Cable housing cutters are a special type of cutter that does a shear cut, I found most general cutters will leave large burs at the end of the cable housing (which you can file away or trim with a blunt cutter) or will not make a clean cut through higher end housing.
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