Both IHP-2 and Triton Ocean World Surveyor look promising, and maybe even the Uranus Orbiter and Probe being switched to Neptune. TRIDENT sadly was cancelled but the future has many surprises for a potential successor to it

Its not really accurate as little is known of Triton, but I tried my best. Credit to u/AssumptionPale7803 and u/CactusCartocratus for the map and the climate legend. I made almost the whole moon a temperate climat as according to the terraforming wiki, Triton would be around 15 degrees on every part of it.

Triton: the largest moon of Neptune may harbor life. Scientists know that it is geologically active, it is thought to have subsurface oceans and scientists have detected a small layer of hydrocarbons on the moon's surface. What do you think?