Ok so I made some tests:

Your planet is far from it's star : 3,41 times farther than the Sun-Earth distance.
1 revolution around the star takes 6,27 years
the global mean temperature is around -117 C, if the atmosphere is the same than on Earth
the diametere of the planet is nearly 4 time Earth's
gravity, I tried to calculate it and I got 1,54 (on Earth it's 9,81) so it's 6,37 time less. I think I made a mistake.
density would be around 1,17 g/cm3 (on Earth it's 5,52) that could be a problem , maybe a weaker magnetic field. But since water is more dominant than on Earth, it could explain a bit of the difference.

Moon B:
mass 2,27 moons (with same density as our Moon)
takes 4 days to obrit around the planet (not sure if that part make sense since our moon takes 28 days and is more or less at the same distance). but at the same time, since both objects are more massive I think B need to move faster to compensate for the increased gravitational pull. Does it make sense ?

moon c: 1,54 moons
take 9,85 days

Moon t : orbit seems more or less stable at 12 000 km but it's pretty much the limit. The hill sphere of moon c is bigger than that but even at 15 000 km, it take less than a week before it change of orbit.
mass : around 0,03 moons
orbit around moon c in 1,11 day


That was the simulator, I did around 150 days. The bodies rotate so fast that 150 days is long enough to know how stable they are. If I increase speed too much the simulator can't get the orbits right and planets get ejected with no reasons. Like a sling.