I can help ya out on your Zebra finch breeding situation and your cage questions.
First off, you want finches to have flying space as flying is their exercise. Unlike larger captive birds, finches do not climb for exercise and entertainment. They need room to fly. I have been told that a minimum space of 30" wide by 18" deep by 24" tall is most healthy per pair, though you may be able to use that space for two pairs of zebras as they are fairly friendly, non-aggressive birds. The key to remember is that width is more important than height. Don't put too many perches in middle areas - give them room to flap those wings.
Most beginner breeders start with Zebras or Societies as they are the easiest to please. Be careful, though, they will breed non-stop - siblings included. Don't let it get out of control! I started one aviary-cage with 3 birds and had 25 six months later. And it gets LOUD! LOL - they love to announce that they all are awake pretty early in the morning.
Put in plenty of nesting materials (coconut fibers are better than typical cotton filler) in addition to pre-fab nests. Always supply more nests than the number of pairs so there are always choices and less fighting will occur. Add fake plants or live plants approved by a professional breeder familiar with toxicity in order to create hiding places, privacy, and places to build their own nests if they so choose.
Provide LOTS of water b/c they love to take bird baths and place food dishes in a variety of places. A variety of seeds mixed with some greens and molting/nestling supplements is best. Always have cuttlebones and/or oyster shells available for the females to replenish the calcium they lose when laying eggs. And of course - MILLET - the favorite snack and a good calorie source, should be abundantly available.
As for temperatures and lighting - you will do best keeping the cage(s) out of drafty areas and at room temperature. Full spectrum lighting is helpful but not required for zebra finches.
Finally, everyone has a different preference on bedding. I personally use crushed walnut on the floors of my cages because birds are usually able to pass that through their digestive systems without trouble. Corn cob is riskier. I avoid using a bar barrier on the cage bottom when breeding in case a baby falls from the nest.
I'm happy to help if you have any other questions! Best of luck and fun!
Shannon (skgserenity@aol.com)