In a two gal, three bettas are definitely way, way, way too much. I'm pretty sure at least one betta will be severely injured or dead. That's overstocking right there...
I wouldn't even touch breeding yet. I've only had my bettas for a year, and I feel it's not enough. For me, I'd rather keep them for about a couple years before considering breeding.
What I know is: You need at LEAST 10 gallons. You must do it right. One thing can go haywire. Lots of money is involved. Lots of money is involved. Lots of jars are involved. Lots of space taken up is involved.