Given that there are virtually no documented records of figure 8 puffers being successfully bred in captivity, I bid you luck. All of the figure 8 puffers you buy at LFS are wild caught.
Your tank is a great size for a figure 8 puffer. I wouldn’t personally keep more than one puffer per community. As they age they will develop aggression towards one another. They also express sexual dimorphism, in which the males and females look exactly the same. Females can grow larger than males in time, but the difference is hardly noteworthy, and not a good basis to sex the fish.
One bit to mention. These are a brackish aquarium fish. They need a specific gravity of at least 1.008, or their immune systems will be compromised. I keep a green spotted puffer in a community of mollies (who also thrive in brackish tanks). I keep my specific gravity at 1.014. The green spotted puffer is a slightly larger version of this. They are both in the Tetraodon
The puffer may bite you, and could potentially break the skin, but it is highly unlikely. They are also non-toxic. The traditional Japanese dish you are referring to is called Fugu
. It is prepared normally species of genus Takifugu
, or Sphoeroides
, or porcupinefish of the genus Diodon
. The liver contains tetrodotoxin, so extreme care in preparation must be taken to avoid puncturing the liver. The figure 8 puffer is in the genus Tetraodon
. So use gloves if you want to, but I don't ever worry about it. If my puffer tried me I would probably give him a good backhand across the tank.
Edit: This is how I do teeth trimmings. Follow this guide exactly. Too much clove oil can euthanize your puffer. https://www.youtube.com/watch?v=VadOW39Cd3I
Alternatively you can feed your puffer a diet of snails and crustaceans to naturally grind down the teeth.