So you believe that dinosaurs were included in the original creation? It's possible. However, I dispute your conclusion from Exodus 20:11. Yes, God created all that we see now. But if the gap theory is correct, the six day creation was to restore the earth to an inhabitable state so that man could live there. Your interpretation raises questions that are impossible to resolve. A pre-Adamic creation makes perfect sense, given that fossils really do exist. One of the greatest Christian scholars ever, Watchman Nee, taught the gap theory. I found him utterly convincing and I've found no plausible refutation either.Everything that currently exists was made during the 6 days:
For in six days the LORD made heaven and earth, the sea, and all that in them is ... Ex 20:11 (KJV).
So anything that was made prior to the 6 days, cannot be in existence today without violating this verse.
There can be no physical evidence, such as a fossil or even one molecule, in existence today that was made prior to the 6 days; without violating this verse. Therefore it's impossible for the "gap theory" to have any existing scientific evidence to support it.
There are questions that I cannot answer, but that applies to many controversial doctrines. One day, we will know all things. I suspect we'll all be surprised by how little we know. "Puzzling reflections in a mirror" as one version puts it.