Everything that you have listed with the exception of the clowns and dwarf angels has yet to be successfully aquacultured in large numbers or even aquacultured at all. The reason they're expensive is because they are not readily available and must be collected.
RCT Hawaii was able to aquaculture some dwarf angels (Interruptus, etc) but nobody on the mainland that does not have access to the ocean has been able to aquaculture any dwarf angels, even flames. They get them to a certain point but after that they cannot provide the food that the larvae need.
You may be successful in breeding clowns but finding the very rare ones that will hold their value over the years is difficult, and getting them to breed is even harder. If you're set on clowns you might want to start with a pair of ocellaris and work your way up (Latz, etc). If you're interested in breeding abberations (picassos, snowflakes) you can expect to pay a lot for a pair now and then have to wait for them to grow up and start spawning. I suspect that by the time you have a spawning pair enough people will be raising them that the price will go down, though I could be wrong.
Unless you raise common fish in large batches the odds of you making a serious profit (unless you're RCT, ORA, or the snowflake breeders) are incredibly slim.
If you are as stubborn as I am and still want to have a go at it, read any and every thread on this site:
http://www.marinebreeder.org/phpbb/index.php
My personal goal is to breed picasso clowns (I lost my spawning pair a few months ago) and someday perhaps have a pair of interruptus, though I will be waiting for RCT to reopen before I purchase my pair. To successfully raise dwarf angel fry you must have specific species of copepod larvae in massive quantities, as well as other microscopic "bugs." I am currently farming mysis and various other copepods in my sump, but I would need a tank dedicated to them if I were to raise them in sufficient quantities...everybody has to start somewhere
