I slept well last night, but I went to bed and woke up a few times thinking about this case. I had some gruesome thoughts. So feel free to ignore me if you have a weak stomach.
The truck and trash can got me thinking about how someone would move a body from a basement. This is assuming that Celina was killed in the basement, of course. And we don't know that yet. But let's assume that for the sake of these points.
1. Celina was a tall girl, I believe. She wasn't light. The person who moved her had to go up stairs. This would be extremely difficult to accomplish without help. My son is only 8, and he weighs 80 pounds. I can't carry him very far when he's asleep. So someone had to be strong or had to have some help from a second person or from some sort of device. My money is on the trash can.
2. Moving a body, especially one that heavy, requires time. That means the killer needed a good 10-15 minutes to commit the crime, dump the body and scram.
3. During daylight hours, the killer surely would expect to be spotted leaving the house, jumping into a vehicle, driving down the road or standing near the river. To reduce this chance, the killer must have acted in the pre-dawn morning hours. While it's possible to dump a body in broad daylight, why would someone dump the body in town? Why not drive 20 minutes into the countryside? The person either couldn't risk being away that long or had some big cajones. My money is on someone acting quickly. That leans away from a stranger, who would have all sorts of time to dump the body in a location that is more difficult to find. Acting hastily also increases the chance of making some blunders and makes it likely that the perpetrator was trying to make sure nobody noticed they were missing.
4. The risk of being caught would have been much greater if people were awake in the house. This seems to suggest that this occurred while everyone but the perpetrator was asleep. With that many people in the house, it's likely that someone was up past midnight. Heck, I don't go to bed until after 2 a.m. a lot of nights. A lot of people are up and moving by 6 a.m. So this really narrows the window. They might be able to narrow it more via phone records and computer usage.
5. I sleep very lightly. If my wife walks into the bedroom, I'm awake. If someone flips a light switch, I'm awake. If someone in the house committed this crime, how did they do it without waking anyone? I can't imagine that they could. If this crime occurred while people were home, someone can tell the police who was up and moving around during the night. Or did the crime occur while the house was mostly empty?
6. The amount of noise should not be underestimated. If there was a struggle at the home, that would be noisy. The biggest noise probably would occur while moving Celina's body. Don't forget that someone went up the stairs and likely used a vehicle. Trucks tend to be noisy. If someone starts a truck in my driveway, I'm probably going to hear it, but I might not. If I'm a killer with a body, though, I'm probably not going to take that risk. That old house probably has some leaky windows and walls. Sound probably travels right through that place.
7. I'm assuming now that the trash can was used to move the body up the stairs. I'm assuming, too, that there is an exterior door to the basement. So the person moved the trash can down the steps, tossed this sweet little girl into the trash can and then moved the can. Well, you can't move a body that heavy without having to drag the can. So there should be marks on the steps and marks on the trash can. Plus, there could be marks on the truck or paint from the truck on the outside of the trash can.
8. A random person isn't going to know that a little girl is living in the basement. Only someone with knowledge could know that. So the person had to know Celina. That dramatically cuts down the list of suspects to locals and people who conversed with her online.
9. A random killer might grab a trash can from the yard. But that person isn't going to bring it back to the house. Only someone who lives in the house would do that. If that trash can was in the back of someone's truck when the police responded, you can draw your own conclusions.
10. They seized two trucks. Why a truck? Someone must have said something. Someone heard a truck running or saw a truck on the road. Did they see the trash can, too? So they decided to check out both of these trucks.
I predict that the trash can will be a key clue in this case. They could link the can to the stairs, to a vehicle and to the blanket/sheet used to wrap Celina. The fact that the can made it back to the house would put the spotlight on someone in that house. Phone and computer records could narrow the window during which the crime was committed, and that could determine who has a solid alibi and who doesn't.