I've got a M/F/F trio of pea puffers in a fluval spec V and they definitely would not be ideal community tank residents. Every now and then they'll get nippy with each other, but with enough sight breaks in the tank they can all get along. In a 55 with a bunch of faster, larger fish I would be worried about the pea puffer being out competed for food along with the fact that he might take a few good chunks out of his tank mates!
Also, amazon puffers are 100% freshwater. I think you may have an amazon puffer confused with a green spotted puffer (who eventually needs full marine salinity) or a figure 8 puffer (a brakish water species that will perish in freshwater). There is a lot of miss information spread about what salinities different puffer species need. Some freshwater species include Pea puffers, amazons, fahakas, Mbus, and congo puffers. Most other puffer species need at least brackish and, for many of them, eventually full marine. Also, if you actually are breeding Amazon puffers that would be a major breakthrough. There is little to nothing known about their reproductive habits aside from the fact that the fry most likely go through a planktonic phase like other pelagic puffer fish after they are broadcast spawned into fast flowing rivers. If you were to spawn these fish, I would find it very unlikely it would be in brackish water.