about moons :

Yes it's possible for a moon to have its own moon but it means that the main moon should be far from the planet and her other moons. The secondary moon would have to be much smaller and orbit very close. Otherwise, the planet will simply garb it. If Ganymede was not tide locked and orbited much farther from Jupiter, she could have a small moon. In fact Jupiter's moons are so close to each other that there is an attraction effect between them. But their orbits are stable for some reason.

Hey, a day on Titan would last for 383 hours, so no more: I don't have enough of 24 hours in a day to do all my stuff! Now you have 383!

If it's a problem, the day length could be shorter if the moon was not tide locked as the planet has her own rotation. In fact, I think this is another problem: having no rotation. You see, according to the climate cookbook, if a planet spins faster you have more prevailing winds. But what happens if the planet does not spin at all?