You may be right about Triton. The current thinking about Triton is that is was a Kuiper Belt object very similar to Pluto. It was captured by Neptune in a retrograde orbit. This capture generated a lot of internal friction melting much or Triton. Triton is still warm from that. Triton may have even collided with other moons, or flung them out of orbit, explaining why Neptune has so few moons.

Also, Triton's retrograde orbit my be generating some internal heat as Neptune slows Triton's obital speed.

Is there a connection between Triton, Pluto/Chiron, Uranus tilt and Uranus’ shattered/reassembled moons?