I know a lot about garbage, but not about Florida garbage, so I am guessing it's the same as here.
1. When you renovate and it's going to take a lot of garbage space, you rent a dumpster. You fill it up and the company that you rented it from hauls it away. They probably bring it to a construction dump place where they put the hazardous materials in a place, recycle what they can, and put in a landfill what is left. There is a huge fine where I live if yu dump hazardous waste such as asbestos or paint, etc.
I imagine it's much more true in Florida because you water is right by the surface.
2. If you are a home owner, you are not allowed to dump construction materials in your personal garbage. You are supposed to bring them to an authorized place, whether that is a construction dump place or a land fill.
3. At our landfill, there are always workers there that direct you to where to bring your trash. They do not accept household garbage-orange peels etc. Refrigerators, furniture, etc. Sounds like that is what they have in OP.
4. Garbage is big business and lucrative. Ours goes to another state to be used for fuel or something. I forget.
5. Construction dumpsters can only contain construction debris. No food, etc. That's why I think the Gano house had their own household garbage can, unless the workers took their McDonald's bags home with them.
6. The dumpster at Gano was not emptied.
7. Someone on this site said that she might have been rolled up in a carpet. That makes sense. It would have been covered with glass and other debris from the fire, as well as soot, if we are to believe ST's statement about soot.
8. She could have been put in a store dumpster, although where I live they are locked, I think. Or an apartment dumpster. I don't know that part. But she wasn't dumped from the Gano dumpster. Or any number of other dumpsters that are available in OP. I think LE is mentioning about a car because she was brought somewhere else in OP and dumped.
9. For sure the perp did not think that she would be found.
10. Carni workers that travel have lots of SO's. Maybe not registered, maybe they are. But when they come to my city, we all say, "Stay away. Don't go there!" In the past , they have been accused of doing improper things with teenagers.
11. Who did it? I don't know. Maybe teenagers who used the house for their activities and were aware of it. Maybe she was killed somewhere else and the carpet was used. Maybe they were familiar with the carpet in the dumpster. Or it was someone else familiar with the dumpster.