I still say he needs more sleep. 12 hours is the beginning of mating season for cockatiels. Did you increase his sleep time? How much? When he is out of the cage, completely rearrange it, toys, perches, even location of food and water. Is he only agressive with the sleep cage? He may think that is his nesting site.
The olympic ring toys with a piece of millet strung through will give him something constructive to do, and when the millet is gone, give him something to take the frustration out on.
It sounds like he is protecting his cage like he would a nest, and until he is pulled out of the breeding mode, he will be frustrated.
Or, conversly, if you want to allow him to get the mating frustration out, you can buy a washable stuffed animal for him to masturbate out of the cage on. While this won't cut down on the agression, it will help with some of his frustration.
While he does not need a mate, you have to realize that he is completely different than Luna was. Males have a strong drive to mate, and it comes earlier in the season than egg laying since they have to get the nest ready and then entice their chosen mate to it.
Sorry I didn't reply about the poo before, does he have red pellets, a toy with red dye, or eat red fresh foods? That is more than likely where it comes from.
Here is a photo of the olympic ring toy, they are cheap but effective.
